Why does George call curleys wife jail bait?

George calls Curley's wife "jail bait" because he sees her as flirtatious and dangerous to be around. The term "jail bait" is slang for a person, usually a young woman, who is sexually attractive but legally too young to consent to sexual activities, which highlights the potential trouble that could arise from being involved with her. George is cautioning Lennie to stay away from her to avoid any complications or conflicts with Curley.