Definitions of ad-lib:

  • noun:   remark made spontaneously without prior preparation
    Example: "His ad-libs got him in trouble with the politicians"
  • verb:   perform without preparation
  • adjective:   with little or no preparation or forethought
    Example: "His ad-lib comments showed poor judgment"
  • adjective:   said or done without having been planned or written in advance
    Example: "He made a few ad-lib remarks"