blunder vs offend

blunder is a noun but offend is not a noun.

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

As verbs, offend is a hypernym of blunder; that is, offend is a word with a broader meaning than blunder:

Other hypernyms of blunder include breach, break, go against, infract, transgress, violate.

blunder (noun)	offend (noun)
an embarrassing mistake

blunder (verb)	offend (verb)
utter impulsively	hurt the feelings of
make one's way clumsily or blindly	cause to feel resentment or indignation
commit a faux pas or a fault or make a serious mistake	strike with disgust or revulsion
	act in disregard of laws, rules, contracts, or promises