Jude Law pulls out all the stops as a profane, bipolar ex-con in Dom Hemingway. Scarlett Johansson leaves the stops pushed all the way in as an alien seductress in Under the Skin.

Though the films are polar opposites, they have two things in common: Both are based in the UK, and both match the personalities of their leading characters.

Dom Hemingway, written and directed by Richard Shepard (The Matador), is loud, abrasive and strangely inconsistent. Though it mostly mirrors the demeanor of the title character during his most reckless and over-the-top moments, it eventually gets bogged down in sentimentality. Moreover, the “plot” really consists of two tacked-together storylines that have little to do with each other.

It’s a shame, because Law’s hair-triggered, verbally explosive safecracker might be fun to watch if the film around him weren’t so incompetently made. The linguistic fireworks begin with the first scene, when the imprisoned Dom expounds on the attributes of his male member (“My cock should hang at the Louvre...”) while being serviced by a fellow inmate.

Soon released after serving 12 years in the slammer, Dom joins former cohort Dickie Black (Richard E. Grant) in a visit to the French estate of wealthy gangster Ivan Fontaine (Demian Bichir). Fontaine wants to reward Dom for refusing to rat him out to the authorities, but Dom seems destined to piss away his good fortune by (1) insulting his dangerous host, (2) making advances on the host’s girlfriend and (3) generally overindulging in sex, drugs and fast cars.

We suspect no good can come of this, and it doesn’t. What we don’t suspect is that after no good comes of it, we’re introduced to a whole new situation that’s equally unpromising. But by this time, we’ve become tired of Dom, who is too self-centered and self-destructive to merit our continued concern.

Taking an entirely different tack from the bombastic Dom Hemingway, Under the Skin is so understated that we have to guess at the identity of its unnamed protagonist (Johansson). The sci-fi tale marks quite a shift for director/co-writer Jonathan Glazer, whose 2000 flick Sexy Beast was dominated by Ben Kingsley’s portrayal of Don Logan, a thug as verbally aggressive as Dom Hemingway but even more dangerous.

It’s an equally big shift for Johansson, who played the warmly supportive but unseen operating system “Samantha” in last year’s Her. In contrast, her Under the Skin character shows few feelings but, thanks to graphic nude scenes, exhibits nearly every inch of her body.

Who is she? A bizarre opening sequence only drops hints, but we suspect she’s an alien being who was sent to Earth to lure men to their deaths. All we know for sure is that she puts on clothes stolen from a dead woman, drives a van around Scotland and chats up passing men. If the men seem to have no families or friends, she seductively invites them to accompany her to a house where they soon find themselves sinking into the glossy floor and being sucked dry by some mystical force.

Though Under the Skin mostly avoids overt violence, there are scenes of shocking callousness. In one, the woman watches impassively as a man tries to save a drowning couple while their toddler cries nearby. In another, she picks up a severely deformed man and exploits his lifelong loneliness as she turns on her seductive charm.

As the film goes on, there are signs that this alien killing machine has begun to develop empathy, or at least curiosity, toward the human species. But the hints are delivered so subtly by Johansson and director Glazer that we don’t know for certain, any more than we know the identity of the silent motorcyclist who seems to serve as the woman’s henchman.

Under the Skin is almost like a work of abstract art, a mood piece that owes more to Daniel Landin’s stark cinematography and Mica Levi’s spooky score than it does to the sparse script. If you demand stories with recognizable characters and traditional plots, you’ll be frustrated. But if you have a taste for mystery, you may well be intrigued.

Dom Hemingway and Under the Skin (both rated R) open Thursday (April 17) at the AMC Lennox Town Center 24. Under the Skin also opens at midnight Thursday at the Gateway Film Center.

Ratings (out of 5 stars):

Dom Hemingway: 2 stars

Under the Skin: 3½ stars