- complacent (adj.)
- 1650s, "pleasing," from Latin complacentem (nominative complacens) "pleasing," present participle of complacere "be very pleasing" (see complacence). Meaning "pleased with oneself" is from 1767. Related: Complacently.
- self-complacent (adj.)
- 1760, back-formation from self-complacency or else from self- + complacent. Related: Self-complacently.