A person, usually female, who puts off the "Do not approach me, you have no chance," vibe. She/He is not interested in dating or sex and prefers to remain friends with many people but not in super close touchy-feely relationships. They usually come off really bitchy and fierce, but it's just part of their natural personality traits.
"It's a shame she's a Touch Me Not, she's pretty hot.."
"Don't even get your hopes up, there is no way in Hell she'd even consider it"