The term 'improvisation' refers to the act of creating something spontaneously without any prior preparation. The crossword solutions for this term are VAMPS (5 letters), ADLIBS (6 letters), FAKESIT (7 letters), and WINGSIT (7 letters). VAMPS stands for 'varying a melody phrase by phrase', which is a form of improvisation used in music. ADLIBS is short for 'ad-libbing', which is a form of improvisation used in acting and comedy. FAKESIT is a term used to describe the act of pretending to know something when one does not, while WINGSIT is a term used to describe the act of making something up on the spot. All of these terms refer to different forms of improvisation.