1A very casual second-person pronoun meaning 'you', used toward close friends or people of lower status. Mostly used by men; it can sound rough or aggressive, so it's never used toward superiors.
お前、さっきから何黙ってるんだよ。
Hey, why have you been quiet this whole time?
お前がそこまで言うなら、信じてやるよ。
If you're saying it that strongly, I'll believe you.
殴り合いの喧嘩の最中、彼は「お前なんかに負けるか」と叫んだ。
In the middle of the fistfight, he shouted, 'I'm not gonna lose to a guy like you!'
兄弟同士だとつい「お前」と呼び合ってしまう。
Between brothers, we end up calling each other 'omae' without meaning to.
2An archaic noun meaning 'before' or 'in the presence of' a deity or a person of high rank, written 御前. Almost never used in modern Japanese.
武士たちは殿の御前に集まり、頭を下げた。
The samurai gathered before their lord and bowed their heads.