slender vs slight

slender is not a noun while slight is a noun.

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

As adjectives, slender and slight are synonyms defined as:

Other synonyms of slender include slim, svelte.

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

slender (adjective)	slight (adjective)
very narrow	(quantifier used with mass nouns) small in quantity or degree; not much or almost none or (with `a') at least some
small in quantity	lacking substance or significance
having little width in proportion to the length or height	being of delicate or slender build
being of delicate or slender build

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