Words you could use instead of the word…

Off

As a verb

Especially for murder

Annihilate

Assassinate

Blow away

Blow out

Bump off

Butcher

Cut down

Dispatch

Do away with

Do in

Eliminate

Eradicate

Execute

Exterminate

Knockoff

massacre

Mow

Mow down

Shoot down

Slaughter

Slay

Snuff

Take out

Terminate

Whack

Wipeout

Zap