Lewis & Short

ădultĕrīnus, a, um, adj. [adulter].

  1. I. Adulterous: liberi adulterino sanguinen nati, Plin. 7, 2, 2, § 14; and of animals, not full-blooded: pullus adulterinus et degener, id. 10, 3, 3, § 10.
    But oftener,
  2. II. That has assumed the nature of something foreign (cf. the etym. of adulter), not genuine, false, counterfeit, impure: symbolum, a false seal, Plaut. Bacch. 2, 3. 32; cf. Paul. ex Fest. p 28 Müll.: adulterina signa dicuntur alienis anulis facta; and Cic.: testamentum signis adulterinis obsignare, Clu. 14: nummus, id. Off. 3, 23: semina, Varr. R. R. 1, 40: claves, Sall. J. 12.