Well, fittingly provided with a suit (4)
I believe the answer is:
ably
'well fittingly' is the definition.
'ably' can be an answer for 'well' (I've seen this in another clue). I'm not certain of the 'fittingly' bit.
'with a suit' is the wordplay.
'with' is a charade indicator (letters next to each other).
'suit' becomes 'bly' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a' next to 'bly' is 'ABLY'.
'provided' is the link.
Can you help me to learn more?
(Other definitions for ably that I've seen before include "In capable manner" , "In a competent fashion" , "Competently" , "With competence" , "In proficient manner" .)