When she found out that the report wasn't ready, she was not a 'happy camper'. [=she was angry or upset]
Rangers warned 'campers' that leaving food outside might attract bears.
A careless 'camper' accidentally started a fire in the woods.
(..) without a major-league screw-up. I didn't screw up. I cleaned the entire coliseum. And vacuumed. Don't let him get into your head, okay? We have a dead camper walking. Dead camper walking, here. Thanks. This is friendship. I'm just playing, just trying to have a little fun. It's all right. (..)2013 Percy Jackson: Sea of Monsters