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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]

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

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

See also: unprepared, unscripted

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

Encyclopedia: Ad lib