fasten on vs espouse

fasten on and espouse both are verbs.

Word	Noun	Adjective	Verb	Adverb
fasten on	No	No	Yes	No
espouse	No	No	Yes	No

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

fasten on: adopt
espouse: take up the cause, ideology, practice, method, of someone and use it as one's own

Other hypernyms of fasten on include adopt, embrace, sweep up.

fasten on (verb)	espouse (verb)
adopt	take up the cause, ideology, practice, method, of someone and use it as one's own
	choose and follow; as of theories, ideas, policies, strategies or plans
	take in marriage; married