Lewis & Short

admissārĭus, a, um, adj. [admitto], sc. equus, asinus, etc.,

  1. I. a horse, ass, etc., that is used for breeding, a stallion, etc.: equus, Varr. R. R. 2, 7: asinus, id. ib. 2, 8.
    Hence, metaph. subst.,
  2. II. Of a sensual, lewd man: scitus admissarius, Plaut. Mil. 4, 3, 19: admissarius iste, sic ad illius orationem adhinniit, * Cic. Pis. 28, 69 (cf. adhinnio); Sen. Q. N. 1, 16.