fluff vs boo-boo

fluff and boo-boo both are nouns.

Word	Noun	Adjective	Verb	Adverb
fluff	Yes	No	Yes	No
boo-boo	Yes	No	No	No

As nouns, boo-boo is a hypernym of fluff; that is, boo-boo is a word with a broader meaning than fluff:

Other hypernyms of fluff include bloomer, blooper, blunder, boner, botch, bungle, flub, foul-up, fuckup, pratfall.

fluff (noun)	boo-boo (noun)
a blunder (especially an actor's forgetting the lines)	an embarrassing mistake
something of little value or significance
any light downy material

fluff (verb)	boo-boo (verb)
ruffle (one's hair) by combing the ends towards the scalp, for a full effect
erect or fluff up
make a mess of, destroy or ruin