mid-14c., profitabilite, "usefulness, use," from profitable + -ity or from Old French profitablete. Sense of "quality of being profitable, gainfulness" is by 1890.
Entries linking to profitability
profitable adj.
c. 1300, "yielding spiritual or moral benefit, useful," from profit (v.) + -able or from Old French profitable, porfitable. From mid-14c. as "advantageous, expedient, helpful." Specific sense of "money-making" is attested from 1758. Related: Profitably; profitableness.
-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]