| up on one's ear |
| upper crust |
| upper-crust |
| up poo creek |
| ups and downs |
| up shit's creek |
| up shit's creek without a paddle |
| up the boohai |
| up the creek |
| up the walls |
| up the yin-yang |
| up to here |
| up to no good |
| up to scratch |
| up to something |
| up with the chickens |
| up with the lark |
| use a sledgehammer to crack a nut |
| used to |
| use one's head |
| use one's noggin |