What is the meaning of Ouch?

An expression of one's own physical pain.

An expression in sympathy at another's pain.

A reply to an insult seen as savage (frequently one that is tongue-in-cheek or joking).

An expression of disappointment.

Expressing surprise at the high price of something.

Something that causes discomfort or pain.

To exclaim "ouch!" in discomfort or pain.

Alternative form of ouche

interjection expressing a sharp pain: ouch!

Source: wiktionary.org