1. turn up one's nose
(idiomatic, with "at") To regard with contempt or scorn, especially in conjunction with the gesture of raising one's nose; to treat with contempt or scorn; to ignore or disregard in a contemptuous or scornful way.
(idiomatic, with "at") To refuse, especially with disgust, contempt or scorn, and especially in conjunction with the gesture of raising one's nose; to refuse with apparent disregard about offending the offerer.
I tried to help, but they turned up their noses at my advice.