adj

• (of behavior, usage, or milieu) Informal; relaxed.
  "tone in casual interactions"
• (of clothing or utensils) Designed for informal or everyday use.
  "pants in the casual wear collection"

noun

• (British, Australia, New Zealand) A worker who is only working for a company occasionally, not as its permanent employee.
• (UK, historical) A member of a group of football hooligans who wear expensive designer clothing to avoid police attention; see casual (subculture).
  "At 15, he became a casual: one of the label-wearing, wedge-flicking, swaggering hooligan peacock boys who dominated the north-west when I was growing up. Casuals were working-class lads (called Perry boys in Manchester) who loved football, fighting and brilliant sportswear."
• (UK, historical) One who receives relief for a night in a parish to which he or she does not belong; a vagrant in the casual ward.
  "During the great prevalence of vagrancy, the cost of the sick was far greater than the expense of relief. In the quarter ending June 1848, no less than 322 casuals were under medical treatment, either in the workhouse of the Wandsworth and Clapham union or at the London Fever Hospital."
• (video games, informal, derogatory) A player of casual games.
  "The devs dumbed the game down so the casuals could enjoy it."