He made preparations to preach differently through a year (10)
I believe the answer is:
apothecary
'he made preparations' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'to preach differently through a year' is the wordplay.
'differently' is an anagram indicator.
'through' means one lot of letters goes inside another (inserted letters go through the word).
'year' becomes 'y'.
'to'+'preach'='topreach'
'topreach' with letters rearranged gives 'pothecar'.
'a'+'y'='ay'
'pothecar' put inside 'ay' is 'APOTHECARY'.
Can you help me to learn more?
(Other definitions for apothecary that I've seen before include "Drug dispenser" , "dealer, old-style" , "Drug supplier" , "Old-style pharmacist" , "Old drug dealer" .)