reverse

noun

1.
a relation of direct opposition
contrary opposite
Derived from:
reverse reverse
2.
the gears by which the motion of a machine can be reversed
reverse gear
Derived from:
reverse
3.
an unfortunate happening that hinders or impedes; something that is thwarting or frustrating
black eye blow reversal setback
4.
the side of a coin or medal that does not bear the principal design
verso
Antonym:
obverse
5.
(American football) a running play in which a back running in one direction hands the ball to a back running in the opposite direction
6.