- defect (n.)
- early 15c., from Middle French defect and directly from Latin defectus "failure, revolt, falling away," noun use of past participle of deficere "to fail, desert" (see deficient).
- defect (v.)
- 1570s, from Latin defectus, past participle of deficere "to fail, desert" (see defect (n.)). Related: Defected; defecting.