A Romantic thriller or a romance thriller is a "narrative that involves "romance and "thriller. "Etymology of the word thrill comes from English root meaning “to pierce”. A thrill is a sharp sensation.
A good thriller provides entertainment by making viewers uncomfortable with moments of suspense, the heightened feeling of anxiety and fright. It makes persons sit on the edge of their seats. A thriller is more a familiar concept and description than a pure "genre. It is not a genre with a precise definition. It canasic thriller trait of suspense, fits with some genres better than with others. For example, "crime, "sci-fi and "romance allow more scope for suspense than "screwball comedies or "musicals do.
Romantic thriller in discussion of genres, is more a metagenre that merges two or more genres together. It is different from established and historically specific cinema movements like "Gothic horror or "Golden Age detective. (thrillers pp. 260 261)  A genre works on two levels. First a specific theme exists. Then general relationships, patterns and structural elements are interwoven to the specific theme. This is why there can be a large variety of visual styles and story structures in romantic thriller.
Notrthrop Frye’s Anatomy of Criticism (1957) suggested four "archetypal categories in literature; comedy, romance, tragedy and irony or satire. In a romance the hero is like us, only slightly superior to others and can behave in remarkable ways, in a world where ‘ordinary laws of nature are slightly suspended'.
The common element in a romantic plot is adventure. There is an adventure or quest where the hero faces ordeals or monsters. There is often a sense of two worlds, the mundane reality and the unknown mysterious. The concept of a maze is seen in romantic thrillers, where the exit or solution is not easily navigated. It’s similar to a metaphor for a journey with blind spots and false turns where some things are hidden.
In the 1935 release of Thirty-Nine Steps , character Richard Hannay leaves a theatre with a mysterious and attractive woman, they begin a romance adventure journey into the world of spies, double agents and espionage. Author "John Buchan was a pioneer of spy thrillers, adding romance and adventure traditions into the then new context of political conflict. The possibility of romance between the mysterious woman, and a decent gentleman was only a minor consideration to "Alfred Hitchcock’s adaptation.
Based on "Raymond Chandler’s First Detective Marlowe novel, The Big Sleep 1946 with Humphrey Bogart and Lauren Bacall, demonstrates the two romantic thriller elements of adventure and dual worlds. The main heroes are brought together in an attempt to save Bacall’s younger sister Vickers. The main adventure sleuth plot has the characters traveling both together and separately. In a common theme, they are from different social worlds, and wouldn’t usually mix. Romance between the two seems hopeless. Parallel to the adventure story unfolding, the romance travels its own labyrinth of truth and deception, to finally overcome issues of mistrust. The story can be summarised as a private detective working for a rich family, investigates a complex case including murder and blackmail while possibly falling in love. Raymond Chandlers’ Marlowe character was described as ‘a knight in dark armor rescuing a lady’. Film adaptations of the novels varied according to the Directors and Producers and their interpretation of the character, using certain traits more than others to tell their story. In a similar way, there is a variety of styles in the adaptations of the "James Bond character. Where Marlowe romanced with quick banter with sexual overtones, Bond seduces in a more physical style.
Opinions will vary on what films are appropriate to mention in this category. This is only a guide. The first list is Hollywood movies. The second is broader and includes international films.
Broader list of examples: