slightly vs slight

slightly is not a noun while slight is a noun.

Word	Noun	Adjective	Verb	Adverb
slightly	No	No	No	Yes
slight	Yes	Yes	Yes	No

slightly (noun)	slight (noun)
	a deliberate discourteous act (usually as an expression of anger or disapproval)

slightly (adjective)	slight (adjective)
	(quantifier used with mass nouns) small in quantity or degree; not much or almost none or (with `a') at least some
	lacking substance or significance
	being of delicate or slender build

slightly (verb)	slight (verb)
	pay no attention to, disrespect

slightly (adverb)	slight (adverb)
to a small degree or extent
in a slim or slender manner