/sulk/ , v.i.
1. to remain silent or hold oneself aloof in a sullen, ill-humored, or offended mood: Promise me that you won't sulk if I want to leave the party early.
n.
2. a state or fit of sulking.
3. sulks , ill-humor shown by sulking: to be in the sulks.
4. Also, sulker . a person who sulks.
[ 1775-85; back formation from SULKY ]