Entries linking to malleability
late 14c., "capable of being shaped or extended by hammering or rolling," from Old French malleable and directly from Medieval Latin malleabilis, from malleare "to beat with a hammer," from Latin malleus "hammer" (from PIE root *mele- "to crush, grind"). Figurative sense, of persons, "capable of being adapted by outside influence" is recorded from 1610s.
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]