Have in stitches is a colloquial phrase that means to make someone laugh uncontrollably. Some of the synonyms for "have in stitches" include "crack up," "split one's sides," "burst out laughing," "fall about," "be convulsed with laughter," "double up with laughter," "roll in the aisles," and "laugh oneself silly." These synonyms perfectly encapsulate the idea of having a good laugh and are often used interchangeably with "have in stitches." However, these phrases are also unique in their own ways and add variety and color to one's everyday language.