One to avoid, Luke at last in contact with his father? (6)
I believe the answer is:
evader
'luke at last in contact with his father?' is the definition.
The definition suggests a singular noun which matches the answer.
'one to avoid' is the wordplay.
'one' becomes 'r' (I can't explain this - if you can you should give a lot more credence to this answer).
'to' says to put letters next to each other (I've seen this in other clues).
'avoid' becomes 'evade' (evading is a kind of avoiding).
'r' after 'evade' is 'EVADER'.
Can you help me to learn more?
(Other definitions for evader that I've seen before include "One who dodges, tax say" , "Dodger" , "Person who avoids" , "One escaping by guile" , "One avoids or circumvents" .)