Lewis & Short

dēfectīvus, a, um, adj. [deficio,

  1. I. no. III.), imperfect, defective (post-class.): et abortiva genitura, Tert. adv. Val. 14: febris, intermittent fever, Cael. Aur. Acut. 2, 10.
  2. II. In gramm.: nomina, verba, some of whose forms are wanting, defective, Charis. 3.