fewer vs less

fewer and less both are adjectives.

Word	Noun	Adjective	Verb	Adverb
fewer	No	Yes	No	No
less	No	Yes	No	Yes

fewer (adjective)	less (adjective)
(comparative of `few' used with count nouns) quantifier meaning a smaller number of	(comparative of `little' usually used with mass nouns) a quantifier meaning not as great in amount or degree
	(nonstandard in some uses but often idiomatic with measure phrases) fewer
	(usually preceded by `no') lower in quality

fewer (adverb)	less (adverb)
	used to form the comparative of some adjectives and adverbs, indicates that the adjective or adverb is less of something
	comparative of little