Lewis & Short

ūsūrārĭus, a, um, adj. [usura].

  1. I. That serves or is fit for use, of which one has the use or enjoyment, = usuarius: puer, Plaut. Curc. 3, 12: uxor, id. Am. 1, 2, 36.
  2. II. Of or belonging to interest or usury, that pays interest: aera, Plaut. Truc. 1, 1, 53: pecunia, at interest, Dig. 16, 2, 11: debitum, ib. 3, 5, 5 fin.; 3, 5, 37 fin.: debitor, ib. 21, 1, 7.