U - Poker Dictionary
The first player to act after the blind bets is said to be under the gun. See also position and straddle.
I'll play those cards occasionally, but never under the gun.
When two hands face off, the underdog is the one that's less likely to win than the other. As with many of the terms in this dictionary, this isn't poker terminology, this is just English.
Aces up is two pair with aces as the higher pair. Kings up is two pair with kings as the higher pair. Are you getting this?
In stud games, your face-up, exposed cards are also just called your up cards.