Wordnet 3.0
ADJECTIVE (1)
1. 
 very funny; 
- Example: "a killing joke"- Example: "sidesplitting antics"[syn: killing, sidesplitting]
WordNet (r) 3.0 (2006):
sidesplitting
    adj 1: very funny; "a killing joke"; "sidesplitting antics"
           [syn: killing, sidesplitting]