Answer:

limiter

Answer	Crossword Clue
LIMITER	One imposing restrictions
LIMITER	Restraint
LIMITER	Source of restrictions

LIMITER	Rationer.
LIMITER	That which bounds.
LIMITER	Circumscriber.
LIMITER	Stinter.
LIMITER	Confiner.
LIMITER	Restricting factor.
LIMITER	Electronic device.
LIMITER	Electrical restricting device

LIMITER	One who puts on a cap
LIMITER	Constraint
LIMITER	One putting on a cap