WordWeb Online

1. With little or no preparation or forethought
   "his ad-lib comments showed poor judgment";
   - extemporaneous, extemporary, extempore, impromptu, offhand, offhanded, off-the-cuff, unrehearsed
    
2. Said or done without having been planned or written in advance
   "he made a few ad-lib remarks";
   - spontaneous, unwritten

1. Remark made spontaneously without prior preparation
   "his ad-libs got him in trouble with the politicians"

1. Perform without preparation
   "he ad-libbed a speech at the wedding";
   - improvise, improvize [non-standard], extemporize, extemporise [Brit], wing it [informal], wing [informal]

1. Without advance preparation
   "he spoke ad lib";
   - ad libitum, spontaneously, impromptu

Derived forms: ad-libbed, ad-libbing, ad-libs

See also: unprepared, unscripted

Type of: comment, do, execute, input, perform, remark

Encyclopedia: Ad-lib