充 fill up

JEWISH people like to fill up on Eastern European traditional dishes like blintzes and knish.

I decapitated the cow and found that its belly was full of human legs! What do you have to say about that, PETA? Yeah, I thought so.

plentiful, full ★☆☆☆☆ F
充 (fill up) + 実 (truth) = 充実した (plentiful, full)

a somewhat formal way to say, "full, satisfactory, plentiful"

charge a battery ☆☆☆☆☆
充 (fill up) + 電 (electricity) = 充電 (charge a battery)

charge a battery (no stars, but it demonstrates the 'fill up' meaning)

suppliment ☆☆☆☆☆
補 (supplement) + 充 (fill up) = 補充 (suppliment)

to suppliment, (a shortfall or deficit) or replenish (fluids, vitamins to replenish strength, restock the store-room) - it's like 補う, but the nuance is that you are restocking a supply of something which has dwindled.