defend vs stand firm

defend and stand firm both are verbs.

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

As verbs, stand firm is a hyponym of defend; that is, stand firm is a word with a more specific, narrower meaning than defend:

defend (verb)	stand firm (verb)
argue or speak in defense of	refuse to abandon one's opinion or belief
state or assert	stand up or offer resistance to somebody or something
be on the defensive; act against an attack
protect against a challenge or attack
protect or fight for as a champion
fight against or resist strongly
be the defense counsel for someone in a trial