1. 
[syn: ad-lib, extemporaneous, extemporary, extempore, impromptu, offhand, offhanded, off-the-cuff, unrehearsed]
The Collaborative International Dictionary of English v.0.48:
off-the-cuff \off-the-cuff\ adj.
   with little or no preparation or forethought; unrehearsed;
   extemporaneous; offhand. his off-the-cuff remarks offended
   many people; an off-the-cuff toast
   Syn: ad-lib, extemporaneous, extemporary, extempore, offhand,
        offhanded, unpremeditated, unrehearsed.
        [WordNet 1.5]
WordNet (r) 3.0 (2006):
off-the-cuff
    adj 1: with little or no preparation or forethought; "his ad-lib
           comments showed poor judgment"; "an extemporaneous piano
           recital"; "an extemporary lecture"; "an extempore skit";
           "an impromptu speech"; "offhand excuses"; "trying to
           sound offhanded and reassuring"; "an off-the-cuff toast";
           "a few unrehearsed comments" [syn: ad-lib,
           extemporaneous, extemporary, extempore,
           impromptu, offhand, offhanded, off-the-cuff,
           unrehearsed]