Definition from Wiktionary, the free dictionary
- Rhymes: -uːst
Origin unknown. The verb is first recorded 1815; the noun, 1825.
boost (plural boosts)
- A push from behind, as to one who is endeavoring to climb; help.
- (automotive engineering) A positive intake manifold pressure in cars with turbochargers or superchargers.
push from behind
Derived terms 
- To lift or push from behind (one who is endeavoring to climb); to push up; hence, to assist in overcoming obstacles, or in making advancement.
- (slang) To steal.
to lift or push from behind