In the past, American English being employed too much (7)
I believe the answer is:
overuse
'being employed too much' is the definition.
(overuse is the condition of being used too much)
'in the past american english' is the wordplay.
'in the past' becomes 'over'.
'american' becomes 'us' (abbreviation for United States).
'english' becomes 'e' (abbreviation).
'over'+'us'+'e'='OVERUSE'
(Other definitions for overuse that I've seen before include "Excessive employment" , "Oeuvres (anag.)" , "Wear out" , "Excessive utilisation" , "Employ too much" .)