interjection
Casual, often masculine interjection used to get someone's attention, express surprise, or urge action. Can sound rough or familiar.
おい、ちょっと待ってくれ。
Hey, wait a minute.
おい、何やってるんだ！
Oi, what are you doing?!
pronoun
Only with reading おい
Kansai dialect first-person pronoun. Used mainly by men in casual settings. Equivalent to standard 俺 or 僕.
おい、そんなん知らんわ。
I don't know anything about that.
おいがやるさかい、任しとき。
I'll do it, so leave it to me.
Standard Japanese masculine first-person pronoun; おい is its Kansai dialect equivalent.
The interjection is of native origin, likely from a natural exclamation. The Kansai pronoun is a dialectal variant of 俺 (おれ).