jackknife vs clasp knife

jackknife and clasp knife both are nouns.

Word	Noun	Adjective	Verb	Adverb
jackknife	Yes	No	Yes	No
clasp knife	Yes	No	No	No

As nouns, jackknife and clasp knife are synonyms defined as:

jackknife and clasp knife: a large knife with one or more folding blades

jackknife (noun)	clasp knife (noun)
a dive in which the diver bends to touch the ankles before straightening out	a large knife with one or more folding blades
a large knife with one or more folding blades

jackknife (verb)	clasp knife (verb)
dive into the water bending the body at the waist at a right angle, like a jackknife