An automatic response to a stimulus without conscious thought.

A response or reaction to a particular situation or event.

किसी विशेष स्थिति या घटना पर प्रतिक्रिया।

English Usage: His reflex action was to defend himself when attacked.

Hindi Usage: जब हमला किया गया तो उसकी प्रतिक्रिया खुद का बचाव करना था।