Collocations for reflex - noun

fast, good, lightning, quick
He reacts with lightning fast reflexes.

poor
automatic
natural
conditioned

trigger
The rapid movement of an object close to the eye triggers an automatic reflex.

control
hone, sharpen
The training is designed to sharpen the fighter's reflexes.

slow
Alcohol can slow your reflexes.

suppress
test
The doctor tested her reflexes.

action, response
Almost as a reflex action, I grab my pen as the phone rings.

by reflex
Almost by reflex, he helped himself to a drink.