They are chin-deep in water.

水淹到他们的下颚。

youdao

Jill crossed her legs and rested her chin on one fist, as if lost in deep thought.

吉尔两腿交叉，下巴抵在拳头上，似乎陷入了沉思。

《柯林斯英汉双解大词典》

The brows were so drawn that there were two deep lines above the beaked nose, and the chin was thrust forward defiantly.

他双眉紧锁，鹰钩鼻上方隆起两道深深的皱纹，下巴不肯屈服地向前突出。

youdao

Also in the group of donated works is a stylized royal portrait from the late 16th century, "Commemorative Head of an Oba, " which shows the ruler's head chin-deep in a collar made from coral beads and capped with a crown made from braided strings and other beads.

WSJ: Boston Museum Gets Major Gift of African Art from Lehman Heir