An imbecile, nincompoop, moron, 'tard, ass for brains, brainless whackjob, ninny, vacuous toffee nosed malodorous pervert, brazen fool, incompetent waste of time, failure waiting to happen, disaster in process, simpleton, witling, ass, chowder head, dunce, ignoramus, numskull, lout, oaf, beetle head, mutton head, mullet head, addle head, addle pate, dunderpate, lackwit, lunkhead, clod, gowk, clotpate, lummox, rube, half wit, noodle head, or other type of person who is mostly useless, and is, at the utmost effect, taking up space here on earth.

This word can be useful for insulting someone, or just in spite when you've run out of logical arguments to a statement with which you disagree.