Hard men in sanctuary disarm a bull (6)
I believe the answer is:
dehorn
'disarm a bull' is the definition.
I can't tell whether this defines the answer.
'hard men in sanctuary' is the wordplay.
'hard' becomes 'h' (abbreviation used in pencil classifications).
'men' becomes 'or' (military abbreviation for Other Ranks).
'in' is an insertion indicator.
'sanctuary' becomes 'den' (I've seen this in other clues).
'h'+'or'='hor'
'hor' put within 'den' is 'DEHORN'.
Can you help me to learn more?
(Other definitions for dehorn that I've seen before include "Remove (bull's or sheep's) outgrowths" , "make drastic cuts" , "Remove hard growths from heads of cattle or deer" .)