formalwear

[fawr-muh l-wair] /ˈfɔr məlˌwɛər/
noun
1.
clothing designed for or customarily worn on formal occasions, as tuxedos and evening gowns.
Compare evening dress.
Origin
formal1 + wear
Examples from the web for formalwear
  • They dress in vintage formalwear instead of storm trooper costumes.
  • In the spring, donate new or gently-used formalwear so teens in foster care can dress up for prom and graduation events.