idiomaticity

(uncountable) The quality of being idiomatic.

(linguistics, countable, rare) The state of a linguistic expression which exists when the expression exhibits semantic-pragmatic divergence, when the semantic value of the expression differs from its pragmatic value; that is to say, idiomaticity exists when the inherent meaning of the words expressed does not match the meaning of the expression as understood by the users: the sayer(s) and hearer(s).

(countable, rare) An instance or category of instances of that quality.