殺雞焉用牛刀

don't use a sledgehammer on a nut / aquila non capit muscam

to kill / to murder / to attack / to weaken or reduce / to smart (dialect) / (used after a verb) extremely

fowl / chicken / CL:隻|只[zhi1] / (slang) prostitute

where / how

to use / to employ / to have to / to eat or drink / expense or outlay / usefulness / hence / therefore

ox / cow / bull / CL:條|条[tiao2],頭|头[tou2] / newton (abbr. for 牛頓|牛顿[niu2 dun4]) / (slang) awesome

knife / blade / single-edged sword / cutlass / CL:把[ba3] / (slang) dollar (loanword) / classifier for sets of one hundred sheets (of paper) / classifier for knife cuts or stabs