booster in WordNet English dictionary

1. a person who backs a politician or a team etc.
   "all their supporters came out for the game"; "they are friends of the library"
   supporter  protagonist  champion  admirer  booster  friend 
   
2. an additional dose that makes sure the first dose was effective
   booster  booster dose  booster shot  recall dose 
   
3. the first stage of a multistage rocket
   booster  booster rocket  booster unit  takeoff booster  takeoff rocket 
   
4. an amplifier for restoring the strength of a transmitted signal
   booster  booster amplifier  booster station  relay link  relay station  relay transmitter 
   
5. a thief who steals goods that are in a store
   booster  shoplifter  lifter 
   
6. someone who is an active supporter and advocate
   promoter  booster  plugger 
   

booster in English Wiktionary