ad-lib ad-lib /ˈædˈlɪb/

adjective

1. () With little or no preparation or forethought  ( extemporaneous , extemporary , extempore , ad-lib , impromptu , off-the-cuff , offhand , offhanded , unrehearsed )
   with little or no preparation or forethought
    His ad-lib comments showed poor judgment
   his ad-lib comments showed poor judgment
    An extemporaneous piano recital
   an extemporaneous piano recital
    An extemporary lecture
   an extemporary lecture
    An extempore skit
   an extempore skit
    An impromptu speech
   an impromptu speech
    Offhand excuses
   offhand excuses
    Trying to sound offhanded and reassuring
   trying to sound offhanded and reassuring
    An off-the-cuff toast
   an off-the-cuff toast
    A few unrehearsed comments
   a few unrehearsed comments
   
2. Said or done without having been planned or written in advance  ( ad-lib , spontaneous , unwritten )
   said or done without having been planned or written in advance
    He made a few ad-lib remarks
   he made a few ad-lib remarks
   

noun

1. Remark made spontaneously without prior preparation  ( ad-lib )
   remark made spontaneously without prior preparation
    His ad-libs got him in trouble with the politicians
   his ad-libs got him in trouble with the politicians
   

verb

1. Perform without preparation  ( ad-lib , extemporise [British] , extemporize , improvise , improvize [Non-standard] , wing it [Informal] )
   perform without preparation
    He extemporized a speech at the wedding
   he extemporized a speech at the wedding