1.
side, beside
The area next to or beside something; the side of something.
脇に寄ってください。
Please move to the side.
道の脇に車を止めた。
I parked the car at the side of the road.
脇役だが重要な役だ。
It's a supporting role, but an important one.
脇役 = supporting role/actor
2.
armpit
The hollow area under the arm where it joins the body.
脇が甘い。
His guard is down. / He's careless.
脇が甘い = to be careless, to let one's guard down (idiomatic, from the armpit area being an unguarded spot)
脇に抱えて運んだ。
I carried it tucked under my arm.
脇に抱える = to carry under one's arm
夏になると脇の汗が気になる人が多い。
In summer, many people worry about armpit sweat.
脇 has two main meanings: the side or beside something, and the armpit area.
SENSE 1 — SIDE:
Refers to an area beside or off to the side of the main focus. Often used in compounds and metaphorical expressions.
COMMON COMPOUNDS:
- 脇役: supporting role/actor
- 脇道: side road, digression
- 脇見: looking aside, distraction (脇見運転 = distracted driving)
SENSE 2 — ARMPIT:
The hollow under the arm. 脇の下 is a more specific way to say "armpit."
IDIOM:
脇が甘い means "to be careless" or "to let one's guard down," from the idea that the armpit area is vulnerable.
COMMON PATTERNS:
- 脇に寄る: to move to the side
- 脇に抱える: to carry under one's arm
- 脇を通る: to pass by the side