Twiddle one's thumbs is an idiom that means to do nothing or to WAIT for something to happen. It is often used to describe someone who is bored and has nothing to do. The crossword solutions for this term are IDLE (4 letters), WAIT (4 letters), KILLTIME (8 letters), and PASSTIME (8 letters). All of these words can be used to describe the action of twiddling one's thumbs, as they all mean to do nothing or to WAIT for something to happen.