Incendiary crime of unclothed clergymen (5)
I believe the answer is:
arson
'incendiary crime' is the definition.
(I've seen this before)
'unclothed clergymen' is the wordplay.
'unclothed' says to take the centre.
'clergymen' becomes 'parsons' (parson is a kind of clergyman).
The centre of 'parsons' is 'ARSON'.
'of' acts as a link.
(Other definitions for arson that I've seen before include "Malicious fire-lighting" , "Malicious crime" , "Malicious fire-raising" , "Roans (anag)" , "Crime of fire-setting (5)" .)