Besides being the familiar appellation for a potent alcoholic liquor, the word rum can also mean -- it's a colloquial Briticism -- that something is a little off, a tad peculiar.

Both definitions of the word apply to The Rum Diary, a meandering comic drama based on an early, semi-autobiographical novel by legendary gonzo journalist and hard drinker Hunter S. Thompson.

Johnny Depp, who produced and stars in the film, was a longtime friend of the Thompson. (The writer committed suicide in 2005 by shooting himself in the head.) Depp previously played Thompson's alter ego, Raoul Duke, in Fear and Loathing in Las Vegas, a 1998 Terry Gilliam movie based on another of Thompson's books.

This time around, the Thompsonesque character whom Depp plays is called Paul Kemp, a scruffy journalist and boozehound who moves to Puerto Rico in the waning days of the Eisenhower era to take a job as a reporter at a struggling, English-language newspaper in San Juan.

In between turning out fluffy stories ordered up by his toupee-wearing editor (Richard Jenkins) on pale, plump tourists enjoying themselves while holidaying on the island, Paul quaffs copious quantities of rum and befriends a scruffy set of colleagues that includes a photographer (Michael Rispoli) and a drug-addicted former reporter (Giovanni Ribisi).

A plot, such as it is, kicks in when Paul meets a Sanderson, a smooth-talking ex-reporter turned real estate developer who is plotting to build a huge resort on a pristine piece of beachfront land. Will Paul be co-opted by the corrupt Sanderson's sweet talk and money or will he do what's right and expose the developer and his corrupt cronies?

The movie never finds a rhythm, though it does improve once the plot starts to build. Director-screenwriter Bruce Robinson (Withnail and I) effectively captures the contrasts between the sun-soaked, privileged side and the rum-soaked, seamier side of San Juan life but the movie's major characters remain hazy and mutable.

Depp, while always fun to watch, phoned this one in. He has played this character before -- think of Paul as an updated Captain Jack, minus the dreads -- and relies heavily on a sneer and a quirked eyebrow.

Eckhart is amusing, equal parts suave and sleaze as the developer, while Amber Heard, playing his sex kitten girlfriend, hasn't much of a role other than to look fetching, which she indeed does.

This being a movie based on a Thompson work, there is the requisite hallucinatory sequence involving drug taking. It's actually one of the funnier bits in the movie (Paul thinks a friend's tongue is lengthening astonishingly), going on just long enough to score comically but without stretching on too long.

Hardcore Thompson fans (and Depp fanatics) will want to see Rum Diary. For anyone else, if the choice is between seeing the movie and lingering for two hours over a tasty rum cocktail with a friend while solving the world's problems (or discussing fashion or sports), consider the latter.