defend vs hold back

defend and hold back both are verbs.

Word	Noun	Adjective	Verb	Adverb
defend	No	No	Yes	No
hold back	No	No	Yes	No

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

defend: be on the defensive; act against an attack
hold back: hold back, as of a danger or an enemy; check the expansion or influence of

Other hyponyms of defend include bulwark, protect, ward off, arrest, check, contain, stop, turn back.

defend (verb)	hold back (verb)
argue or speak in defense of	prevent the action or expression of
state or assert	hold back, as of a danger or an enemy; check the expansion or influence of
be on the defensive; act against an attack	hold back; keep from being perceived by others
protect against a challenge or attack	secure and keep for possible future use or application
protect or fight for as a champion	wait before acting
fight against or resist strongly	refrain from doing
be the defense counsel for someone in a trial