not bad vs bully

not bad is not a noun while bully is a noun.

Word	Noun	Adjective	Verb	Adverb
not bad	No	Yes	No	No
bully	Yes	Yes	Yes	No

As adjectives, not bad and bully are synonyms defined as:

Other synonyms of not bad include bang-up, corking, cracking, dandy, great, groovy, keen, neat, nifty, old, peachy, slap-up, smashing, swell.

not bad (noun)	bully (noun)
	a cruel and brutal fellow
	a hired thug

not bad (adjective)	bully (adjective)
excellent	excellent

not bad (verb)	bully (verb)
	discourage or frighten with threats or a domineering manner; intimidate
	be bossy towards