To be exceptionally irritable, annoyed, or grumpy. John is always like a bear with a sore head first thing in the morning—it's best not to even talk to him until he's had his coffee.Janet was like a bear with a sore head when she found out she had missed her connecting flight.
to be in a bad mood which causes you to treat other people badly and complain a lot If his newspaper doesn't arrive by breakfast time he's like a bear with a sore head.