袒胸露背

tǎnxiōnglùbèi

to be naked to the waist

Wiktionary

Entry Composition

1 袒胸 tǎnxiōng to bare the breast
=2 露背 lòubèi (of a garment) backless; halterneck
=2 露背 lùbèi
  1. (of garments) backless
  2. backless