IPA: /ˈboʊl.stər.ər/
KK: /ˈboʊlstərər/
A person or thing that supports or strengthens something else.
The bolsterer of the team provided encouragement and motivation to all the players.
Bolsterer → It is formed from "bolster" (from Old English *bolster*, meaning a support or cushion) and "-er" (meaning a person who). A bolsterer is a person who provides support or reinforcement.
Think of a 'bolster' as something that supports or cushions, and the '-er' indicates a person who does that — a bolsterer is someone who supports.