sinuosity (n.)

"full of turns and curves, undulating, serpentine," 1570s, from Latin sinuosus "full of curves, folds, or bendings," from sinus "curve, fold, bend" (see sinus). Sometimes in late 19c. especially "morally crooked, deviating from the right." Alternative sinuose in the same sense is by 1829. Related: Sinuously; sinuousness.

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]