Is litter a verb or an adjective?

The Word litter is a verb (litter, litters, littering, littered) and a noun (litter, litters). Examples:

Verb: When people litter public areas, it show a lack of respect for others.

Noun: Wind blown litter was piling up at the end of the alley.

Noun: Our cat had a litter of kittens.

Noun: We'll need a lot more cat litter as those kittens mature.

Noun: They placed the wounded man on a litter.