It's a simple word, and maybe one of the first you'll learn in Italian. But it can still cause a bit of confusion.
Aiuto is a masculine noun meaning help, aid or assistance.
“Aiuto!” simply means “help!” and is used just like in English – mostly in emergencies.
Aiutare is the verb form: to help.
– Aiuto, affogo!
– Help, I’m drowning!
Sometimes people get confused because the noun aiuto looks the same as the first-person conjugation of aiutare: (io) aiuto
– ti aiuto
– I'll help you/Let me help
Much like in English, Italian speakers might use either the noun or verb to say similar things.
– Ringraziamento per tutto l'aiuto
– Thank you for all the help
– Grazie per avermi aiutata con i compiti
– Thanks for helping me with my homework
What about when you want to ask for assistance politely, in a non-life-threatening situation?
– puoi/potresti aiutarmi
– can you/could you help me?
The pronoun mi becomes a suffix of the verb – apparently just because that rolls off the tongue more easily than puoi aiutare mi.
Be careful though. This is the informal way to ask for help, which you'd use with friends and family, but maybe not somewhere like the town hall or doctor's office.
In more formal situations, use potrebbe aiutarmi? (for addressing one person) / potreste aiutarmi? (when speaking to more than one person.)
To be extra polite, you can add a per favore either at the beginning or at the end.
– Mi scusi, potresti aiutarmi per favore?'
– Excuse me, could you help me please?
Use these and you'll definitely be the politest person in the anagrafe.
And in shops, you'll often hear this:
– Posso aiutarti/la?
– Can I help you? (formal/informal)
To which you could always reply,
– No grazie, do solo un'occhiata
– No thanks, I'm just looking