The opposite of "too funny for words" would be something that is not funny at all, or in other words, completely unfunny. Some antonyms for this phrase could be humorless, dull, tedious, unamusing, unentertaining, or boring. When something isn't funny, it can be difficult to find anything to laugh about, which can be disappointing if you were hoping for some amusement. While humor is subjective and varies from person to person, it's clear that the opposite of "too funny for words" is something that fails to elicit any sort of laughter or amusement, leaving us feeling bored or disappointed.