All mouth and no trousers—(UK derog.) said of somebody who talks or boasts a lot but doesn’t take any action (also: all talk and no trousers).
- How much longer will it take to realize that the leader is all mouth and no trousers?
All mouth and trousers— = all mouth and no trousers.
- Jack is all mouth and trousers, he never does anything he says he will.