What does absurd mean?
The definition of absurd
Ab*surd”, a.
Etym: [L. absurdus harsh-sounding; ab + (prob) a derivative fr. a root svar to sound; not connected with surd: cf. F. absurde. See Syringe.]

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

Synonyms
— Foolish; irrational; ridiculous; preposterous; inconsistent; incongruous.
— 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.

Ab*surd”, n.
An absurdity. [Obs.] Pope.