• 腕うで — arm
• 腕前うでまえ — skill; craftsmanship
• 腕力わんりょく — physical strength of the arms
• 腕試うでだし — test of one’s skill
• 腕相撲うでずもう — arm wrestling
• 名腕めいうで — master hand; top-notch worker
• 腕章わんしょう — armband
• 敏腕びんわん — capable; efficient (lit. “nimble arm”)

腕 combines the body radical ⺼（にくづき） with the phonetic part 宛 (reading clue for ワン). From the body + phonetic, the meaning developed to the physical arm and, by extension, one’s ability — the skill you can “show with your hands.”

Think of 腕前（うでまえ） — your level of skill on display. In crafts, cooking, or sports, people often judge the result “by your 腕.” Training builds muscle memory; that’s why 腕 naturally extends from the limb to the idea of proficiency.