Corrupt English teaching system (4)
I believe the answer is:
rote
'teaching system' is the definition.
(as in learning by rote)
'corrupt english' is the wordplay.
'corrupt' becomes 'rot'.
'english' becomes 'e' (abbreviation).
'rot'+'e'='ROTE'
(Other definitions for rote that I've seen before include "Way of learning" , "By . . . . means by memory - that tore it" , "mindless activity?" , "Mechanical routine" , "By . . . . - by memory without thinking" .)