If you call somebody vile, you better have a good reason because it can be a very hurtful word to use and the person must really sicken you.
"I can't believe he can be so vile"
It could also refer to their personality and general characters which in total amount to them being well and truly repulsive.
"Yuck, he/she is vile".
"How can you do that? Thats just vile!"