defect (n.) Look up defect at Dictionary.com
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," from de- "down, away" (see de-) + combining form of facere "to do, make" (from PIE root *dhe- "to set, put").
defect (v.) Look up defect at Dictionary.com
1570s, from Latin defectus, past participle of deficere "to fail, desert," from de- "down, away" (see de-) + combining form of facere "to do, make" (from PIE root *dhe- "to set, put"). Related: Defected; defecting.