1
general::
In an irritable or depressed state of mind. For example, Dad's in a bad mood, so don't ask for anything right now. The antonym, in a good mood, refers to a cheerful, well-disposed state of mind, as in When the boss is in a good mood our whole day goes well. The phrase in a mood, meaning "disposed" or "inclined," dates from about A.D. 1000. Also see IN THE MOOD.
American Heritage Idioms
2
general::
Phrase(s): *in a bad mood
sad; depressed; grouchy; with low spirits. (*Typically: be ~; get ~; put someone ~.) • He’s in a bad mood. He may yell at you. • Please try to cheer me up. I’m in a bad mood.
McGrawhill's American Idioms And Phrasal Verbs