is a specific kind of: alter, change, modify.

is a broader term that covers: clutter, clutter up | clog, overload | brim | farce, stuff | stuff | bolster, pad | populate | top off | heap | overfill | ink | fill again, refill, replenish | prime | line | complete | impregnate, saturate | impregnate, infuse, instill, tincture | electrify | lube, lubricate | surcharge | lade, laden, load, load up | charge, load | deluge, flood, inundate, swamp | pack ... show more.

cause: fill, fill up.

is the opposite of: empty.

see also: fat, fatten, fatten out, fatten up, fill out, flesh out, plump, plump out | fill in, shade.

derivation: filling | filler | filler, makeweight | filler | fill, filling.