Green’s Dictionary of Slang

blue-nosed adj.

[bluenose n.1 ]
(orig. US)

1. [mid-19C+] (also bluenose) pertaining to being a New Englander, esp. as blue-nosed Yankee.

2. [mid-19C+] (also blue, bluenose) rigidly, repressively puritan.

3. [1950s] snobbish.