jackass jackaroo • jackassery · · · Info · Definitions · Synonyms · Characters · · jackass · · Text Latin · · Script 7 · · Length Definitions · · · (noun) a man who is a stupid incompetent fool. Synonyms: fathead, goof, goofball, bozo, goose, cuckoo, twat, zany. · · Noun Definition 1 (noun) male donkey. Synonyms: jack. · · Noun Definition 2 Synonyms · · · fathead · · Synonym 1 goof · · Synonym 2 goofball · · Synonym 3 bozo · · Synonym 4 goose · · Synonym 5 cuckoo · · Synonym 6 twat · · Synonym 7 zany · · Synonym 8 jack · · Synonym 9 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 j latin small letter j U+006A k latin small letter k U+006B s latin small letter s U+0073