prēˈpäst(ə)rəs, prə̇ˈ- adjective
Etymology: Latin praeposterus, literally, reversed, from prae- pre- + posterus next, following — more at posterior
1.
a. : contrary to nature, reason, or common sense : absurd , nonsensical
so many seemingly incredible and preposterous things were true nevertheless — Ellen Glasgow
b. : ridiculous in appearance or manner : grotesque
false nose and preposterous spectacles — Eric Keown
uses its preposterous Elizabethan collar as a storehouse for food — Bill Beatty
2. : having or placing something first that should be last
an infuriating book … a preposterous one in inverting with absolute conviction a comfortable and rarely questioned order of values — Times Literary Supplement
Synonyms: see foolish