Synonyms for Ludicrous:

adj.

absurd (adjective)
illogical, bizarre, irrational, contradictory, foolish, ridiculous, implausible, silly, paradoxical, inconsistent, impossible, inane, absurd, invalid, nonsensical, preposterous, anachronistic, idiotic, fallacious, outlandish, crazy, farcical, incongruous, eccentric, meaningless, self-contradictory, senseless.
amusing (adjective)
comical.
bizarre (adjective)
curious, eccentric, ridiculous, oddball, weird.
cockeyed (adjective)
absurd.
comic/comical (adjective)
humorous.
crazy (adjective)
derisory, insane, outrageous, senseless.
extravagant (adjective)
implausible.
ludicrous (adjective)
comical, grotesque, foolish, silly, laughable, crazy, bizarre, outlandish, incongruous, farcical, nonsensical, preposterous.
ridiculous (adjective)
dubious, nonsensical, grotesque, foolish, comical, outlandish, oddball, eccentric, laughable, weird, outrageous, preposterous, curious, absurd, ridiculous, poppycock, incredible, crazy, bizarre, silly, farcical.

n.

childish, insane, over-the-top, mad, not in your right mind/not right in the head. laughter, laughing. laughable (noun)
study at absurd.
ludicrous (noun)
derisory, nonsensical, farcical, laughable, humorous, humourous, preposterous, absurd, foolish, ridiculous.

Other synonyms:

insane, over-the-top, mad. laughing. childish. Other relevant words:
childish, humourous, mad, derisory, insane, laughing, over-the-top, humorous, absurd.

Usage examples for ludicrous

  1. It was both ludicrous and incomprehensible. – Riders of the Silences by Max Brand
  2. The whole costume formed a rather ludicrous picture. – The Autobiography of St. Ignatius by Saint Ignatius Loyola
  3. A more dejected figure could scarcely be imagined, nor a more ludicrous one, as he limped toward the entrance, hands on hips and himself bent forward forlornly. – Dorothy at Oak Knowe by Evelyn Raymond