“Many of the smaller misdeeds were regarded as exhibitions of an infidelitas, which, however, did not amount to a felonia.” 2 Frederick Pollock & Frederic W. Maitland, The History of English Law Before the Time of Edward I 513–14 (2d ed. 1899).
infidelitas
infidelitas (in-fi-dee-l[schwa]-tas or -del-[schwa]-tas), n. [Latin] Hist. Infidelity; faithlessness to one’s feudal oath.