Top religious school badly hit (6)
I believe the answer is:
zenith
'top' is the definition.
(a zenith is a top or peak)
'religious school badly hit' is the wordplay.
'religious school' becomes 'zen' (school of Buddhism).
'badly' indicates an anagram (letters in the wrong order).
'hit' anagrammed gives 'ith'.
'zen'+'ith'='ZENITH'
(Other definitions for zenith that I've seen before include "Meridian" , "The highest point directly above" , "The highest point, above in the sky" , "Top point" , "Peak" .)