high horse

plural high horses

1. idiomaticAn appearance or sense of smug superiority.

   Lawrence would say no more, so I decided that I would descend from my high horse, and once more seek out Poirot at Leastways Cottage.

   1920, Agatha Christie, The Mysterious Affair at Styles, London: Pan Books, published 1954, page 144

   1 more example

   "I tell you Miss Abbott, it's one thing for England and another for Italy. There we plan and get on high moral horses. here we find what asses we are, for things go off quite easily, all by themselves.

   1905, E. M. Forster, Where Angels Fear to Tread, chapter 6