to reduce the size, amount or number of sth; to kill sb
cut sth down (to…)
to reduce the size, amount or number of sth
We need to cut the article down to 1 000 words.
cut sb downformal
to kill sb
He was cut down by an assassin's bullet.
cut sth down
to make sth fall down by cutting it at the base
to cut down a tree
Definitions from the Oxford Advanced Learner's Dictionary, 9th edition