1. Literally, contort one's face into a disdainful, scornful, or condescending expression because of and directed at someone or something. Sarah just sneered at me when I invited her to my party. The king sneered at the artist's portrait, claiming it looked nothing like him.

2. By extension, to regard someone or something with haughty disdain, scorn, condescension, etc. I feel like the rest of the world is sneering at us because of our outdated, backwards laws. I used to sneer at the idea of working in a cubicle for eight hours a day, but once I had kids and needed steady income, it stopped sounding so unappealing.