Quotes one in a strange sect (5)
I believe the answer is:
cites
'quotes' is the definition.
(I know this)
'one in a strange sect' is the wordplay.
'one' becomes 'i' (Roman numeral).
'in' indicates putting letters inside.
'a strange' is an anagram indicator.
'sect' with letters rearranged gives 'ctes'.
'i' inserted within 'ctes' is 'CITES'.
(Other definitions for cites that I've seen before include "Quotes; mentions in official despatch" , "Mentions as an example" , "Quotes (an author)" , "Quotes as authority" , "Refers to" .)