In good time, like a nobleman quite possibly? (5)
I believe the answer is:
early
'in good time' is the definition.
(being early is arriving in good time)
'a nobleman quite possibly?' is the wordplay.
'a nobleman' becomes 'earl' (earl is a kind of nobleman).
'quite possibly?' becomes 'y' (I can't justify this - if you can you should give a lot more credence to this answer).
'earl'+'y'='EARLY'
'like' is the link.
Can you help me to learn more?
(Other definitions for early that I've seen before include "at start of day" , "Advanced" , "Before due time" , "sooner than expected" , "Beforehand" .)