Hailey Baldwin: Hey Justin, Eat Your Heart Out!!!

Hailey Baldwin's looking a whole lot more grown and sexy than any other teen Justin Bieber might be seeing these days.

The 19-year-old flaunted her model figure Tuesday night in a crop top at the UGG Classic Street event in NYC ... her abs out and gleaming.

Seems like a clear message to Justin ... look what you're missing out on, bud.