infidelitas
From LSJ
Latin > English (Lewis & Short)
infĭdēlĭtas: ātis, f. infidelis,
I unfaithfulness, faithlessness, infidelity: amicitiarum, Cic. Tusc. 5, 22: infidelitatis suspicionem sustinere, * Caes. B. C. 2, 33. — In plur.: quantae infidelitates in amicitiis, Cic. Mil. 26, 69.