clasp vs hold on

clasp is a noun but hold on is not a noun.

Word	Noun	Adjective	Verb	Adverb
clasp	Yes	No	Yes	No
hold on	No	No	Yes	No

As verbs, hold on is a hypernym of clasp; that is, hold on is a word with a broader meaning than clasp:

Other hypernyms of clasp include grasp.

clasp (noun)	hold on (noun)
the act of grasping
a fastener (as a buckle or hook) that is used to hold two things together

clasp (verb)	hold on (verb)
hold firmly and tightly	be persistent, refuse to stop
grasp firmly	stop and wait, as if awaiting further instructions or developments
fasten with a buckle or buckles	hold the phone line open
fasten with or as if with a brooch	hold firmly
	retain possession of