booster - noun

a person who backs a politician or a team etc.

someone who is an active supporter and advocate

a thief who steals goods that are in a store

an amplifier for restoring the strength of a transmitted signal

the first stage of a multistage rocket

an additional dose that makes sure the first dose was effective

booster - thesaurus

admirer   champion   friend   lifter   plugger   promoter   protagonist   shoplifter   supporter