hat
In addition to the idioms beginning with hat, also see at the drop of a hat; brass hat; eat one's hat; hang on to your hat; hang up (one's hat); hard hat; hats off to; keep under one's hat; knock into a cocked hat; pass the hat; pull out of a hat; take one's hat off to; talk through one's hat; throw one's hat in the ring; wear another hat. Also see under cap.