Idiom
whittle something downwhittle (something) down
to gradually reduce or destroy something.By halftime our team's lead had been whittled down to only two points.College is so expensive, after two years, my college fund has been whittled away to almost nothing.
Usage notes: also used in the form whittle away at something:
Over the past year, we've whittled away at our debts.
Etymology: based on the literal meaning of whittle (= to shape a piece of wood by cutting strips or small pieces from it with a knife)