The thriller genre is defined largely by its inclusion of other genres. Thrillers have no set definition, viewers know one when they feel it. This allows for it to merge and blend with other more narratively defined genres like mystery, horror, or crime.

One of the most popular genres throughout time, even casual movie fans can point to some of the genre's most famed films, such as Psycho or Silence of the Lambs. Yet still, despite the genre's enduring popularity, there are many elite thrillers that haven't yet got their due, but one day surely will.

10 'Cop' (1988)

james woods in cop 1988

Cop has a lot going for it, such as the source material, adapted from James Ellroy's Blood on the Moon. Another is the casting where the film stars Lesley Anne Warren, coming off a phenomenal 80s run, as well as James Woods, right in the middle of his excellent 80s stretch. Perhaps most of all, the film, about an obsessive cop who takes the law into his own hands, has style.

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Woods is a true movie star in the lead role, incorporating his trademark brand of intellectualism and sharp sardonicism into a part that in other hands may come off as a second-rate Dirty Harry. Despite all this, Cop wouldn't succeed commercially, grossing less than a measly $2 million. Still, the film is violent and relentless enough that it will surely have an audience out there.

9 'Killer Joe' (2011)

Matthew McConaughey in Killer Joe
Image via LD Entertainment

Killer Joe may not appeal to everybody due to its brutality and sadistic sense of humor. But for those who revel in the delights of savagery, Killer Joe is an inspired work of psychological torment. The movie, about a young man who hires a contract killer to get rid of his mother for the insurance money, is also a new beginning of sorts for its biggest names.

That includes director William Friedkin, one of the defining directors of New Hollywood whose career had tapered off ever since the 1990s. That also includes star Matthew McConaughey who had been making bland rom-coms through the 2000s and used Killer Joe as a means to expand his range, eventually launching the 'McConaissance'. Even though it grossed less than half its budget, Tracy Letts's perverted and uncommonly cultivated script makes Killer Joe an unsavory delight.

8 'Defence of the Realm' (1986)

gabriel byrne and denholm elliott in defence-of-the-realm_

A great political thriller as well as a journalism movie, Defence of the Realm is as smart as they come. Grossing a meager $750 000, the film is a 1970s-style paranoia thriller with David Hare governmental commentary. Following a reporter tracking the conspiracy behind a Parliamentary resignation, the movie may have had the rare privilege of being too clever for mainstream audiences.

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Although a little convoluted at times, the film is truly first-rate, with Gabriel Byrne and Denholm Elliott delivering classy performances. It is also shot very effectively thanks in tandem to director David Drury and cinematographer, the great Roger Deakins. With all the average political thrillers being put out nowadays, fans must yearn for a premier version like Defence of the Realm.

7 '99 Homes' (2014)

andrew-garfield-99-homes-talking

Few neorealist filmmakers have such a heavy heart as Ramin Bahrani. Still a young auteur, Bahrani's career has gone through many up and downs already. His early work, influenced heavily by Italian Neo-Realism, Iranian New Wave, and Bressonian minimalism, achieved great acclaim. As he moved to more mainstream projects, Bahrani has found varied success, but one undeniable triumph is 99 Homes.

Surrounding an evicted family during the Great Recession, 99 Homes is a human drama that is bound by the feeling of dread. It works in part due to the cruelty of the circumstance juxtaposing Bahrani's natural humanity. Regardless of paltry financial success, 99 Homes is a heartbreaking account of the modern American economic landscape.

6 'Dead Ringers' (1988)

The Mantle twins standing together in 'Dead Ringers.'

One of David Cronenberg's best films, Dead Ringers explores identity in a way no other film ever has. Serving as spiritually antithetical but physically identical twin brother gynecologists, Jeremy Irons delivers his acting opus in one of the truly exceptional performances ever put to screen. A vision of undying loyalty, the film was voted the 7th greatest Canadian film ever by the Toronto International Film Festival.

Even for all this praise, Dead Ringers barely broke even at the box office. Like a great thriller, it is pulse-racing and absorbing but without the same visceral propulsion. Instead, Dead Ringers leisurely makes its way to its fatalistic conclusion, like an approaching hurricane in a nearby town. Soon, the film may gain more notoriety as it is set for a remake series for Amazon Prime.

5 'Malice' (1993)

nicole kidman, alec baldwin and bill pullman together in malice_

It's still unclear why Malice hasn't caught on in the way it should have. It has great actors delivering great performances, it has two world-class screenwriters, Aaron Sorkin and Scott Frank, in collaboration. It even has truly quotable, iconic movie moments, highlighted by Alec Baldwin's 'I am God' monologue. It got mixed reviews and did good business, but fans often fail to mention it up there with the most enjoyable, if a bit over the top, 90s thrillers.

The plot, about a con involving a young couple and a handsome surgeon, is pretty clever and well-thought-out. Harold Becker's direction, while a bit ordinary, is serviceable. Besides some delectable dialogue, the casting by Nancy Klopper is immaculate with Baldwin a natural as the scheming and handsome doctor, Nicole Kidman perfect as the callous but innocent wife and Bill Pullman flawless as the pleasant but duped husband.

4 'TransSiberian' (2008)

A screenshot of Woody Harrelson and Emily Mortimer in Transsiberian where he has his hands up and she is hiding behind him in fear
Image via Universum Film

Through films like The Machinist, Beirut, and especially TransSiberian, director Brad Anderson has carved himself a nice little niche as one of the better mid-budget thriller directors of the 21st century. While only grossing less than $6 million against a $15 million budget, TransSiberian uses an eclectic fusion of characters and ambiance to enhance its 'danger on a train' concept.

The setting, a train from Bejing to Moscow, is not as glamorous as some of the vacations Hercule Poirot may have dined on. But that only intensifies the film's tension, as Anderson makes the location a true character. While the slasher-style ending may slightly undermine the careful suspense the movie was building, TransSiberian still works as a stirring and atmospheric journey.

3 'Eye of the Needle' (1981)

donald sutherland and kate nelligan in eye_of_the_needle_

Passing away 18 days shy of his 50th birthday in 1987, Richard Marquand had a very limited peak as a director. Culminating in his turn as the director of Return of the Jedi in 1983, the film that secured Marquand that position was his 1981 spy thriller Eye of the Needle. Led by a spellbinding Donald Sutherland, the movie concerns a Nazi spy who gets stranded on an island off the coast of Scotland.

Patiently plotted and psychologically layered, Eye of the Needle offers a more pensive thriller with emotional intrigue. There is a sexual element to the film as well which is at times bewitching, if rarely actually romantic. Sutherland is the one who makes the film what it is. Tall, brooding and sharp, Sutherland's cerebral menace looms over the entire film.

2 'Cutter's Way' (1981)

jeff bridges and john heard in cutters_way_

Released in 1981, Cutter's Way was one of the foremost cinematic reflections on the 1960s and the Vietnam War, up there with 1981's Four Friends and 1983's The Big Chill. Cynical and abrasive, the film is an autopsy of counterculture disillusionment, with John Heard's performance the beating heart. Grossing less than $2 million, it released to mixed reviews but went on to be lauded.

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Like Heard's Alex Cutter, a crippled Vietnam vet who bears some similarities to Forrest Gump's Lieutenant Dan, the movie is bitter and willing to tear apart anyone in the way of it completing its self-destruction. Lisa Eichhorn is also terrific in a sullen, introspective role, prompting pondering on why she never had a bigger career. The conclusion, keeping with the movie's nature, is shocking, contemptuous, and bleak.

1 'Internal Affairs' (1990)

andy garcia and richard gere in internal_affairs_1990

Not to be confused with the Hong Kong action films of the same name, 1990s Internal Affairs is a spirited take on a familiar genre. Richard Gere stars as Dennis Peck, a corrupt policeman, and womanizer who abuses his power to get what he wants. Gere is brilliant, showcasing a side of him he should have tapped into more, a suaveness crossed with iniquitous sexual deviancy that few actors can truly harness.

Alec Baldwin can harness it, as he did at times in the aforementioned Malice. Pierce Brosnan can harness it, as he did in spades in The Tailor of Panama. Gere rarely did, opting for characters more debonair than guileful. In addition, the combination of Mike Figgis as director and Henry Bean as writer elevate the film past its genre conventions. Two of the most dynamic and bold filmmakers of their time, Figgis and Bean turn Internal Affairs into a wicked crime-thriller.

NEXT: The 25 Best Thrillers of the 21st Century (So Far)