Look down your nose at somebody/something
Definition 1 of 1
Pro Tip 1/3Negative Connotation
Carries a critical tone; suggests looking at someone as if they're inferior. 
She looked down her nose at the amateurish painting.
Pro Tip 2/3Visual Imagery
Imagine someone physically tilting their head up, nose in the air, as a sign of rejection. 
At the staff meeting, he looked down his nose at every suggestion.
Pro Tip 3/3Social Context
Often used in situations where one's social status or sophistication is compared. 
He looks down his nose at fast food restaurants.