The term "rib-tickling" is used to describe something that is amusing, funny, and hilarious. However, if you are looking for antonyms for this word, you can consider words like dull, tedious, boring, dry, uninteresting, monotonous, and serious. These words are the opposite of the lively and entertaining meaning of "rib-tickling." For instance, if a movie or TV show fails to make you laugh or smile, you can describe it as dull or tedious rather than rib-tickling. Similarly, a person who is somber or moody would be the antithesis of someone with a rib-tickling personality.