1.
chin
The front part of the face below the mouth.
彼は顎に髭を生やしている。
He has a beard on his chin.
顎を引いて姿勢を正した。
I pulled my chin in and corrected my posture.
顎を手でささえて考えている。
She's resting her chin on her hand and thinking.
二重顎が気になる。
I'm worried about my double chin.
彼は部下を顎で使うような人だ。
He's the kind of person who bosses his subordinates around.
顎で使う is an idiom meaning to order people around arrogantly.
2.
jaw
The bone structure that forms the framework of the mouth.
顎が外れそうなくらい笑った。
I laughed so hard I thought my jaw would dislocate.
硬いものを食べて顎が疲れた。
My jaw got tired from eating something hard.
歯医者で顎を大きく開けてと言われた。
The dentist told me to open my jaw wide.
顎の関節が痛くて口が開けにくい。
My jaw joint hurts and it's hard to open my mouth.
上顎と下顎の噛み合わせが悪い。
The bite alignment between my upper and lower jaw is off.
顎 refers to both the chin and jaw area.
COMMON PATTERNS:
- 顎を引く (pull chin in, good posture)
- 顎を上げる (raise chin, look up/act proudly)
- 顎が外れる (jaw dislocates; figuratively: laugh hard)
- 顎髭 (chin beard, goatee)
- 二重顎 (double chin)
BODY PART CONTEXT:
Face parts:
- 頬 (cheek)
- 額 (forehead)
- 唇 (lips)
- 眉 (eyebrow)
IDIOMS:
顎で使う = to order someone around arrogantly (literally: direct with one's chin)