"state or quality of being nameless," 1820; see anonym "nameless person" + -ity. In same sense anonymousness is recorded from 1802.
Entries linking to anonymity
anonym n.
1812, "nameless person," from French anonyme, from noun use of Latin anonymus, from Greek anonymos "without a name" (see anonymous). The meaning "fictitious name" is recorded from 1864.
-ity
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]