re‧flex /ˈriːfleks/ noun [countable]
[Date: 1500-1600; Language: Latin; Origin: past participle of reflectere; ⇒ reflect]

1. reflexes [plural]
a) the natural ability to react quickly and well to sudden situations
have good/quick/slow reflexes
A tennis player needs to have very quick reflexes.
b) a sudden uncontrolled movement that your muscles make as a natural reaction to a physical effect:
Doctor Mulholland tested Jennifer’s reflexes (=especially by hitting her knee with a special rubber hammer).

2. reflex action something that you do without thinking, as a reaction to a situation

[TahlilGaran] Dictionary of Contemporary English ▲

reflex
noun
ADJ. good, lightning, quick | poor | automatic | natural | conditioned
VERB + REFLEX trigger The rapid movement of an object towards the eye triggers the blink reflex.
control | sharpen, speed up The training is designed to sharpen the fighter's reflexes.
slow (down) Alcohol can slow your reflexes.
suppress | test The doctor tested her reflexes.
REFLEX + NOUN action, reaction Almost as a reflex action, I grab my pen as the phone rings.
PREP. by ~ Almost by reflex, he helped himself to a drink.

[TahlilGaran] Collocations Dictionary ▲