err vs fall for

err and fall for both are verbs.

Word	Noun	Adjective	Verb	Adverb
err	No	No	Yes	No
fall for	No	No	Yes	No

As verbs, fall for is a hyponym of err; that is, fall for is a word with a more specific, narrower meaning than err:

Other hyponyms of err include misremember, slip up, stumble, trip up, misjudge.

err (verb)	fall for (verb)
to make a mistake or be incorrect	fall in love with; become infatuated with
wander from a direct course or at random	be deceived, duped, or entrapped by