うっ

interjection

oof; ugh; ulp

An exclamation of sudden pain, surprise, or being winded. Often used when one is hit, stumbles, or feels a sharp sensation.

• うっ、お腹なかが痛いたい。

  Oof, my stomach hurts.

• うっ、ぶつかってすみません。

  Oof, sorry for bumping into you.