(often derogatory) silent and withdrawn after being upset
the sulky child
1865, Lewis Carroll, Alice's Adventures in Wonderland
Indeed, she had quite a long argument with the Lory, who at last turned sulky, and would only say, “I’m older than you, and must know better.” And this Alice would not allow, without knowing how old it was, and, as the Lory positively refused to tell its age, there was no more to be said.
noun
A light, two-wheeled, horse-drawn cart used in harness racing.