Answer: impromptu

AnswerCrossword Clue
IMPROMPTUComment, part 3
IMPROMPTUSpur-of-the-moment
IMPROMPTUMakeshift
IMPROMPTUOff the cuff
IMPROMPTULike a jam
IMPROMPTUUnprepared
IMPROMPTUMusical composition
impromptuwithout preparation
impromptu(Latin) improvised, spontaneous / a short piece of impromptu music