clasp knife vs pocketknife

clasp knife and pocketknife both are nouns.

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

As nouns, pocketknife is a hypernym of clasp knife; that is, pocketknife is a word with a broader meaning than clasp knife:

clasp knife: a large knife with one or more folding blades
pocketknife: a knife with a blade that folds into the handle; suitable for carrying in the pocket

Other hypernyms of clasp knife include pocket knife.

clasp knife (noun)	pocketknife (noun)
a large knife with one or more folding blades	a knife with a blade that folds into the handle; suitable for carrying in the pocket