Impulsive response, almost very French and to a greater extent not English (6)
I believe the answer is:
tremor
'impulsive response' is the definition.
(I know that tremor is a type of impulsive response)
'almost very french and to a greater extent not english' is the wordplay.
'almost very french' becomes 'tre' (I can't justify this - if you can you should believe this answer much more).
'and' says to put letters next to each other.
'to a greater extent' becomes 'more' (synonyms).
'not' indicates named letters should be taken away.
'english' becomes 'E' (abbreviation).
'more' with 'e' taken out is 'mor'.
'tre'+'mor'='TREMOR'
Can you help me to learn more?
(Other definitions for tremor that I've seen before include "Small vibration" , "Vibration - shaking" , "Involuntary shudder" , "make one shake" , "Strong shake" .)