hold fast vs bind

hold fast is not a noun while bind is a noun.

Word	Noun	Adjective	Verb	Adverb
hold fast	No	No	Yes	No
bind	Yes	No	Yes	No

As verbs, hold fast and bind are synonyms defined as:

Other synonyms of hold fast include adhere, bond, stick, stick to.

As verbs, bind is a hyponym of hold fast; that is, bind is a word with a more specific, narrower meaning than hold fast:

hold fast (noun)	bind (noun)
	something that hinders as if with bonds

hold fast (verb)	bind (verb)
stick to firmly	cause to be constipated
	form a chemical bond with
	bind by an obligation; cause to be indebted
	make fast; tie or secure, with or as if with a rope
	fasten or secure with a rope, string, or cord
	provide with a binding
	stick to firmly
	secure with or as if with ropes
	wrap around with something so as to cover or enclose
	create social or emotional ties