technicality (n.)

1610s, "skilled in a particular art or subject," formed in English from technic + -al (1), or in part from Greek tekhnikos "of art; systematic," in reference to persons "skillful, artistic," from tekhnē "art, skill, craft" (see techno-).

The sense narrowed to "having to do with the mechanical arts" (1727). Basketball technical foul (one which does not involve contact between opponents) is recorded from 1934. Boxing technical knock-out (one in which the loser is not knocked out) is recorded from 1921; abbreviation TKO is from 1940s. Technical difficulty is from 1805.

word-forming element making abstract nouns from adjectives and meaning "condition or quality of being ______," from Middle English -ite, from Old French -ete (Modern French -ité) and directly from Latin -itatem (nominative -itas), suffix denoting state or condition, composed of -i- (from the stem or else a connective) + the common abstract suffix -tas (see -ty (2)).

Roughly, the word in -ity usually means the quality of being what the adjective describes, or concretely an instance of the quality, or collectively all the instances; & the word in -ism means the disposition, or collectively all those who feel it. [Fowler]