Douglas Harper's Etymology Dictionary
"quality of being cat-like," 1848; see feline + -ity.
Wiktionary
n. 1 (context uncountable English) The state of being feline. 2 (context countable English) Any feline characteristic.
Usage examples of "felinity".
The saurians passed away long before felinity evolved into even its most archaic forms or became sentient.
Rhiow, within Iau, rejoiced at the sight of it, for now she saw that this was where the River of Fire belonged—at the roots of the Tree: at the scene of the battle, where the souls of all felinity would at one time or another pass through the place of Choice, of the Fight, the gaming-ground that was the mother of all bouts of hauissh.
William Lyon Phelps has very effectively captured the secret of felinity when he says that the cat does not merely lie down, but "pours his body out on the floor like a glass of water".
For their part, the house cats returned his gaze, affirming that each and every one of them knew their place in the hierarchy of felinity without a word, or a hiss, having to be spoken.