informal

/ɪnˈfɔrməl/
adjective
  1. Relaxed, friendly, or casual; not formal or official.
    • The dress code for the party is informal, so wear jeans.
    • We had an informal meeting in the coffee shop.
    • He used informal language when talking to his friends.
  2. Not following the official rules or procedures.
    • The group operates as an informal network of volunteers.
    • An informal survey showed that most people preferred the new design.
    • They reached an informal agreement without signing a contract.
What does "informal" mean? | whatsthatwordmean | whatsthatwordmean