Here are some more examples of interjections and their definitions:
Ahem! - This is sound of someone clearing his or her throat, and means “Can I have your attention?” or “Please listen to me”.
Ah! - This is used when someone is scared.
Boo! - Used to scare someone or to voice disapproval.
Yuck! - Shows dislike or disgust.
Hmm. - This can mean you are thinking or hesitating.
Oops! - An exclamation people use when they accidentally do something.
Whoops! - Another exclamation people use when they accidentally do something.
Phew! - This expresses relief or that you are glad something is over.
Whoa - This can show surprise or amazement.
Yahoo! - Expresses joy or happiness.