From Longman Dictionary of Contemporary Englishbe in a moodbe in a moodBAD-TEMPEREDto feel unhappy, impatient, or angry and to refuse to speak normally to other people He’s been in a real mood all day. Don’t talk to her. She’s in one of her moods (=used about someone who is often unhappy, angry etc). → mood
Examples from the Corpus
be in a mood• She knew that Brian was in a mood this morning.• If only Grace were in a mood slightly more in tune with her own.• She's been in a mood all day.• Virginia liked to watch them when they were in a mood that required that they be handled with extreme care.• It looked safe enough, and neither of us was in a mood to test it.• Neither of us was in a mood to dicker.• When he got home that evening he could smell that Val was in a mood.• If you are in a mood to be frightened by what is beyond the curtains, Marcus's selection does the job. 