hold up vs buoy up

hold up and buoy up both are verbs.

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

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

Other hyponyms of hold up include scaffold, block, carry, chock, buoy, pole, bracket, underpin, prop, prop up, shore, shore up, truss, brace.

hold up (verb)	buoy up (verb)
cause to be slowed down or delayed	become more cheerful
be the physical support of; carry the weight of	keep afloat
hold up something as an example; hold up one's achievements for admiration	make more cheerful
rob at gunpoint or by means of some other threat
continue to live and avoid dying
resist or withstand wear, criticism, etc.
resist or confront with resistance