An "unofficial" (not recognized by dictionaries) slang descriptor for a person/thing/action/object, etc., or a combination of, which is one or more of the following:

a waste of time, abandoned, abject, abominable, abortive, absurd, afraid, aimless, anxious, apprehenaive, arid, arrested, assailable, atomic, awful, baby, babyish, backward, bad, banal, barmy, barren, base, baseless, bastard, beastly, beggarly, behind, beside the question, blah, bland, bogus, bomb, bootless, boyish, brainless, bromidic, bummer, caitiffcapricious, careless, catchpenny, characterless, cheap, checked, cheesy, childish, childlike, clichéd, cloying, coarse, colorless, common, commonplace, confusing, contemptible, cotemptible, controvertible, conventional, cool, corn, cornball, corny, corrupt, counterproductive, cowering, cracked, crap, crappy, craven, crazy, crud, cruddy, daffy, daft, dastardly, dazed, dead, deadpan, deficient, degraded, degrading, dejected, delayed, delusive, dense, dense, deplorable, depraved, despicable, destitute, detestable, devoid, diffident, dim, diminutive, dippy, directionless, dirty, disgraceful, dishonest, dishonorable, dismayed, disposable, disreputable, dizzy, dodo, doltish, dopy, dotterel, down, downtrodden, drab, drifting, drudging, dull, dumb, empty, empty-headed, erratic, evanescent, everyday, evildoer, excessive, exhausted, expendable, expressionless, facetious, failed, failing, faint-hearted, fallacious, false, fanciful, fatuous, fawning, featherbrained, feeb...

interfering thoughtless arseholes

A person that automatically does things without thinking about them.

adj. the end result of an overload of multi-tasking, a loss of brain function along with any concept of time, space, or location-often leaving the victim in a state of confusion, wondering where it all began............

D1: Noun; One who has acted in a thoughtless and/or selfish manner to the detriment of others.
D2: Verb; To deliberately act thoughtlessly because you think it's funny even though it's not.
D3: Verb; To intentionally steal a parking space from someone who clearly was waiting before you.

(v.) To refrain from giving a needed ride to friends/coworkers when the opportunity presents itself.

One of the funniest humans alive

He became known on Comedy Central's Daily Show for his thoughtless but hilarious antics.

Then he starred as Brick, a retarded weatherman in the movie Anchorman: The legend of Ron Burgundy where he pretty much stole every scene.

Recently came out with a movie called 40 Year Old Virgin.