He preaches equality (6)
I believe the answer is:
parson
'he preaches equality' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he preaches equality' is the wordplay.
I cannot quite understand how this works, but
'he' could be 'son' and 'son' is present in the answer.
'equality' could be 'par' (synonyms) and 'par' is found in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for parson that I've seen before include "Churchman" , "Aprons (anag.)" , "man of the church" , "Anglican clergyman" , "Rector; clergyman" .)