What is "turn up one's nose"

alt. 1 To make the gesture of raising one's nose, as a sign of scorn, contempt or disgust. 2 (context idiomatic with "at" English) 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. 3 (context idiomatic with "at" English) 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. vb. 1 To make the gesture of raising one's nose, as a sign of scorn, contempt or disgust. 2 (context idiomatic with "at" English) 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. 3 (context idiomatic with "at" English) 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.