Avoid writing to one of those on the run (6)
I believe the answer is:
evader
'one of those on the run' is the definition.
I can't tell whether this definition defines the answer.
'avoid writing' is the wordplay.
'avoid' becomes 'evade' (evading is a kind of avoiding).
'writing' becomes 'r' (I've seen this in other clues).
'evade'+'r'='EVADER'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for evader that I've seen before include "One who avoids tax" , "One avoids or circumvents" , "Person who avoids" , "One escaping by guile" , "Dodger" .)