1) Act grumpily 2) Act pettily peevish 3) Act the sore loser 4) Act the sourpuss 5) Bad-tempered silence 6) Be a poor loser 7) Be a poor sport 8) Be a sourpuss 9) Be a spoil sport 10) Be ill-humored 11) Be in a pet 12) Behave childishly 13) Behave moodily 14) Behave peevishly 15) Brood 16) Brood moodily 1) Brood 2) Mope 3) Mopearound 4) Pout 5) Snit 6) Sulkiness 
[horse] Sulk is a thoroughbred racehorse and winner of the prestigious Prix Marcel Boussac in France. ...
• (n.) A furrow. • (v. i.) To be silently sullen; to be morose or obstinate.
Sulk intransitive verb [ See Sulkiness .] To be silently sullen; to be morose or obstinate. T. Hook. Sulk noun [ Latin sulcus .] A furrow. [ Obsolete] 
[n] - a mood or display of sullen aloofness or withdrawal 2. [v] - be in a huff 3. [v] - be in a huff
noun a mood or display of sullen aloofness or withdrawal; `stayed home in a sulk`
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.