Sort who won't heed the advice "Don't look down"?

SNOB

This person might turn their nose up at you while standing on higher ground.

The clue plays on the word "sort," which can mean a type of person, hinting at the answer being a kind of individual. "Won't heed the advice 'Don't look down'" suggests someone who looks down on others, which is a trait of a snob. The wordplay ties the literal meaning of "look down" to the figurative sense of being condescending.