No the word scanty is not a noun. It is an adjective.

The word 'scanty' is an adjective (scanty, scantier, scantiest), that describes a noun as limited; barely enough; meager, insufficient; inadequate.

The noun form for the adjective scanty is scantiness.

The adverb for for the adjective scanty is scantily.

There is no verb form for the adjective scanty.

The cheerleaders wore scanty outfits.

The opposite of scanty is plentiful. This means that there is plenty of things.

It was a scanty amount of food to feed four people with.