say it: kuhm-PLAY-suhn-see
complacency is a noun meaning "the feeling you have when you are satisfied with yourself". It is pronounced /kəmˈpleɪsənsi/ — kuhm-PLAY-suhn-see. It carries one recorded sense.
the feeling you have when you are satisfied with yourself
“his complacency was absolutely disgusting”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for complacency come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.