offend vs insult

offend is not a noun while insult is a noun.

Word	Noun	Adjective	Verb	Adverb
offend	No	No	Yes	No
insult	Yes	No	Yes	No

As verbs, insult is a hyponym of offend; that is, insult is a word with a more specific, narrower meaning than offend:

Other hyponyms of offend include affront, diss, lacerate, sting, abase, chagrin, humble, humiliate, mortify.

offend (noun)	insult (noun)
	a deliberately offensive act or something producing the effect of deliberate disrespect
	a rude expression intended to offend or hurt

offend (verb)	insult (verb)
hurt the feelings of	treat, mention, or speak to rudely
cause to feel resentment or indignation
strike with disgust or revulsion
act in disregard of laws, rules, contracts, or promises