A
female, typically one with small breasts. (Often used in a negative context.)
Males
may be called chestlets as an insult, much
like calling a male a "little girl". (Also, may be a more demeaning insult than "manlet".)
"I don't see how anyone can
like chestlets, more
meat on a woman is better!"
"Shut up, you chestlet."
"Forget that
slag, she's a chestlet anyway, not worth your time."