City hit hard (4)
I believe the answer is:
bath
'city' is the definition.
(English city)
'hit hard' is the wordplay.
'hit' becomes 'bat' (batting is a kind of hitting).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'bat'+'h'='BATH'
(Other definitions for bath that I've seen before include "Home fixture (for City?)" , "Water container for washing" , "Scene of ablutions" , "Somerset city with abbey and medicinal waters" , "Large washtub - English city" .)