risible \RIZ-uh-buhl\ (adjective) - 1 : Capable of laughing; disposed to laugh. 2 : Exciting or provoking laughter; worthy of laughter; laughable; amusing. 3 : Relating to, connected with, or used in laughter; as, "risible muscles."
"The subject of these remarks was a slumbering figure, so muffled in shawl and cloak, that it would have been matter of impossibility to guess at its sex but for a brown beaver bonnet and green veil which ornamented the head, and which, having been crushed and flattened, for two hundred and fifty miles, in that particular angle of the vehicle from which the lady's snores now proceeded, presented an appearance sufficiently ludicrous to have moved less risible muscles than those of John Browdie's ruddy face." -- Charles Dickens, 'The Life And Adventures Of Nicholas Nickleby'
Late Latin rīsibilis, from Latin rīsus, past participle of rīdēre, to laugh.