informal Meaning, Definition & Usage

  1. adjective not formal
    • conservative people unaccustomed to informal dress
    • an informal free-and-easy manner
    • an informal gathering of friends
  2. adjective satellite not officially recognized or controlled
    loose.
    • an informal agreement
    • a loose organization of the local farmers
  3. adjective used of spoken and written language
  4. adjective satellite having or fostering a warm or friendly and informal atmosphere
    cozy; intimate.
    • had a cozy chat
    • a relaxed informal manner
    • an intimate cocktail lounge
    • the small room was cozy and intimate

WordNet

In*form"al adjective
Etymology
Pref. in- not + formal.
Definitions
  1. Not in the regular, usual, or established form; not according to official, conventional, prescribed, or customary forms or rules; irregular; hence, without ceremony; as, an informal writting, proceeding, or visit.
  2. Deranged in mind; out of one's senses. Obs.
    These poor informal women. Shak.

Webster 1913