Such a one may suit you (6)
I believe the answer is:
tailor
'suit you' is the definition.
'tailor' can be an answer for 'suit' (thesaurus). I'm not sure about the 'you' bit.
'such a one' is the wordplay.
I cannot quite see how this works, but
'a' is present in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
This explanation may well be incorrect...
'may' is the link.
Can you help me to learn more?
(Other definitions for tailor that I've seen before include "One makes suits etc. to measure" , "Fashion" , "Seamster" , "Maker of clothes, men's mostly" , "Cut" .)