To lift or push from behind (one who is endeavoring to climb); to push up.
(by extension) To help or encourage (something) to increase or improve; to assist in overcoming obstacles.
This campaign will boost your chances of winning the election.
To steal.
To jump-start a vehicle by using cables to connect the battery in a running vehicle to the battery in a vehicle that won't start.
To give a booster shot to.
To amplify; to signal boost.