Synonyms: laughable, absurd, foolish, comical, funny, hilarious, etc.
Definition of ridiculous
adjective
1. causing or worthy of ridicule or derision; absurd; preposterous; laughable:
a ridiculous plan
2. Slang. absurdly or unbelievably good, bad, crazy, etc.:
The concert was ridiculous, their best performance ever!
Examples:
This ridiculous situation borders upon comedy. 'You look ridiculous!' Nick laughed. I've never heard anything so ridiculous. The deal seems so attractive it would be ridiculous to say no.