mediocrity n.

c. 1400, mediocrite, "moderation; intermediate state or amount," from Latin mediocritatem (nominative mediocritas) "a middle state, middling condition, medium," from mediocris "of middling height or state, moderate, ordinary," figuratively "mediocre, mean, inferior," literally "halfway up a mountain" (see mediocre). Neutral at first; disparaging sense "quality of being moderate or middling in ability, accomplishment, etc." began to predominate from late 16c. The meaning "person of mediocre abilities or attainments" is from 1690s. Before the tinge of disparagement crept in, another name for the Golden Mean was golden mediocrity.