Head examiner slammed poor English teaching primarily (12)
I believe the answer is:
phrenologist
'head examiner' is the definition.
(phrenology is a pseudoscience studying the head)
'slammed poor english teaching primarily' is the wordplay.
'slammed' is an anagram indicator.
'primarily' suggests taking the first letters.
The first letter of 'teaching' is 't'.
'poor'+'english'='poorenglish'
'poorenglish' anagrammed gives 'phrenologis'.
'phrenologis'+'t'='PHRENOLOGIST'
(Other definitions for phrenologist that I've seen before include "One supposedly reading character in head shape" , "Student of skull shape" , "One drawing conclusions from a skull's shape" .)