Boost: God is English! (5)
I believe the answer is:
raise
'boost' is the definition.
(I've seen this in another clue)
'god is english' is the wordplay.
'god' becomes 'Ra' (Egyptian god).
'english' becomes 'E' (abbreviation).
'ra'+'is'+'e'='RAISE'
(Other definitions for raise that I've seen before include "climb" , "Cultivate by growing" , "Contact" , "Wage increase" , "Heighten" .)