Rush impressed English (8)
I believe the answer is:
stampede
'rush' is the definition.
(I've seen this before)
'impressed english' is the wordplay.
'impressed' becomes 'stamped' (stamping is a kind of impressing).
'english' becomes 'E' (abbreviation as in OED).
'stamped'+'e'='STAMPEDE'
(Other definitions for stampede that I've seen before include "Sudden dash of a group of startled animals" , "Panicky run" , "Flight of cattle in panic" , "Sudden mass rush" , "Sudden rush of frightened animals" .)