Yours, Etc.: Origins and Uses of 8 Sign-Offs
1837, from Pennsylvania German outch, cry of pain, from German autsch. The Japanese word is itai. Latin used au, hau.
An injury; a hurt: A very serious injury is a ''big'' ouch
[1873+; fr the pained interjection ouch fr German, probably Pennsylvania German, autsch, found by 1838]