pushup

As a noun pushup

is .

As a verb boosting is

.

As nouns the difference between pushup and fallback

is that pushup is while fallback is an act of falling back.

As an adjective fallback is

that can be resorted to as a fallback.

As nouns the difference between pushup and boost

is that pushup is while boost is a push from behind, as to one who is endeavoring to climb; help.

As a verb boost is

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.

As nouns the difference between pullup and pushup

is that pullup is an exercise done for strengthening the arms and upper body, in which one lifts one's own weight while hanging from a bar while pushup is .