Lewis & Short

perpĕtŭārĭus, a, um, adj. [perpetuus], constant, permanent; always employed, constantly engaged in any business or calling (post-Aug.): mulio, Sen. Apoc. 6, 2.
Subst.: perpĕtŭārĭus, ii, m., a fee-farmer, hereditary tenant, Cod. Just. 11, 70, 5.