[until hell freezes over] {adv. phr.}, {slang} Forever, for an eternity. […]

[until the last gun is fired] See: [TILL THE LAST GUN […]

[unturned] See: [LEAVE NO STONE UNTURNED].

[up a stump] {adj. phr.}, {slang} Stumped; blocked; mixed up or […]

[up a tree] {adv.} or {adj. phr.} 1. Hunted or chased […]

[up against] {prep. phr.} Blocked or threatened by. * /When she […]

[up against it] {adj. phr.}, {informal} Faced with a great difficulty […]

[up and about] or [around] {adv. phr.} Recovered and able to […]

[up and at them] 1. {adv. phr.} Actively engaged in a […]

[up for grabs] {adj. phr.}, {informal} Available for anyone to try […]