The adjective distinct is used to describe things that are clearly distinguished from others.

What type of word is distinctness?

dis·tinct. adj. 1. Readily distinguishable from all others; discrete: on two distinct occasions.

Is distinctness a noun?

from The Century Dictionary.

noun The quality or state of being distinct, in any sense of that word. noun Synonyms Distinctness, Distinction (see distinction ), plainness, perspicuity, explicitness, lucidity.