One who's concerned about English occupation (6)
I believe the answer is:
career
'occupation' is the definition.
(career is a kind of occupation)
'one who's concerned about english' is the wordplay.
'one who's concerned' becomes 'carer'.
'about' means one lot of letters goes inside another.
'english' becomes 'e' (abbreviation).
'carer' going around 'e' is 'CAREER'.
(Other definitions for career that I've seen before include "Make rapid progress" , "Tear" , "Employment history" , "Vocation; rush" , "Working lifetime" .)