Lewis Short
infĭdēlĭtas (noun F) : infidelis
* 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.
Charlton T. Lewis, Charles Short, A Latin Dictionary