stock up vs understock

stock up and understock both are verbs.

Word	Noun	Adjective	Verb	Adverb
stock up	No	No	Yes	No
understock	No	No	Yes	No

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

stock up: amass so as to keep for future use or sale or for a particular occasion or use
understock: stock with less than the usual or desirable number or quantity

Other hyponyms of stock up include overstock.

stock up (verb)	understock (verb)
amass so as to keep for future use or sale or for a particular occasion or use	stock with less than the usual or desirable number or quantity