hold up vs retard

hold up is not a noun while retard is a noun.

Word	Noun	Adjective	Verb	Adverb
hold up	No	No	Yes	No
retard	Yes	No	Yes	No

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

Other hypernyms of hold up include decelerate, slow, slow down, slow up.

hold up (noun)	retard (noun)
	a person of subnormal intelligence

hold up (verb)	retard (verb)
cause to be slowed down or delayed	lose velocity; move more slowly
be the physical support of; carry the weight of	cause to move more slowly or operate at a slower rate
hold up something as an example; hold up one's achievements for admiration	slow the growth or development of
rob at gunpoint or by means of some other threat	be delayed
continue to live and avoid dying
resist or withstand wear, criticism, etc.
resist or confront with resistance