力一杯
ちからいっぱい with all one's strength; with might and main
Why it means this
力 (strength) + 一杯 (a cupful, i.e. to the full) — with all one's might, to the very limit of one's strength.
Breakdown
- 力 ちから power, strength, strong
- 一 イチ one, one radical (no.1)
- 杯 さかずき counter for cupfuls, wine glass, glass
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