Meaning
ouch!, ow!
- an exclamation expressing sudden physical pain or distress

In a sentence
Ahi! Mi sono punto con una spina.
Ouch! I pricked myself on a thorn.
Ahi, che male alla testa!
Ow, what a headache!
Ahi! Fai attenzione con quella porta!
Ouch! Be careful with that door!
Usage notes
- Spelled with an silent 'h' in the middle: 'ahi', not 'hai' (which is the verb 'avere').