(uncountable) Lack of cleanliness.

(uncountable) Dirt, filth.

(uncountable) Indecency; corruption; unkindness, meanness, spite, harshness, cruelty.

(uncountable) Unpleasantness, disagreeableness (to the senses).

(countable) A nasty action, object, quality, etc. (all senses of nasty).