Tom: Hey! How come you're all dressed up?
Bob: Well, I have my first date tonight with Sara, and I want to look sharp.
Tom: Nice! Hope you two have a great first date!
Julie: So are your ready for your first day at your new job?
Chrissy: You know it! I went shopping yesterday and found this really nice dress. Look!
Julie: That is perfect! You are going to look really sharp.
Meaning: "To look sharp" is used when someone dresses up and looks really handsome or pretty. Usually this is done for a special occasion.