stand up vs stand firm

stand up and stand firm both are verbs.

Word	Noun	Adjective	Verb	Adverb
stand up	No	No	Yes	No
stand firm	No	No	Yes	No

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

Other hypernyms of stand up include hold out, resist, withstand.

stand up (verb)	stand firm (verb)
defend against attack or criticism	refuse to abandon one's opinion or belief
refuse to back down; remain solid under criticism or attack	stand up or offer resistance to somebody or something
be standing; be upright
put into an upright position
rise to one's feet
rise up as in fear
resist or withstand wear, criticism, etc.