What does "absurd" mean?

Absurd: Contrary to reason or propriety; obviously and fiatly opposed to manifest truth; inconsistent with the plain dictates of common sense; logically contradictory; nonsensical; ridiculous; as, an absurd person, an absurd opinion; an absurd dream. This proffer is absurd and reasonless. Shak. 'This phrase absurd to call a villain great. Pope. p. 9 -- Absurd, Irrational, Foolish, Preposterous. Of these terms, irrational is the weakest, denoting that which is plainly inconsistent with the dictates of sound reason; as, an irrational course of life. Foolish rises higher, and implies either a perversion of that faculty, or an absolute weakness or fatuity of mind; as, foolish enterprises. Absurd rises still higher, denoting that which is plainly opposed to received notions of propriety and truth; as, an absurd man, project, opinion, story, argument, etc. Preposterous rises still higher, and supposes an absolute inversion in the order of things; or, in plain terms, a "putting of the cart before the horse;" as, a preposterous suggestion, preposterous conduct, a preposterous regulation or law.