jackknife jack kerouac • jackknife clam · · · Info · Definitions · Synonyms · Characters · · jackknife · · Text Latin · · Script 9 · · Length 2 · · Syllables Definitions · · · (noun) a large knife with one or more folding blades. Synonyms: clasp knife. · · Noun Definition 1 (noun) a dive in which the diver bends to touch the ankles before straightening out. · · Noun Definition 2 (verb) dive into the water bending the body at the waist at a right angle, like a jackknife. · · Verb Definition 1 Synonyms · · · clasp knife · · Synonym 1 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 f latin small letter f U+0066 i latin small letter i U+0069 j latin small letter j U+006A k latin small letter k U+006B n latin small letter n U+006E