Chose finest editor (6)
I believe the answer is:
picked
'chose' is the definition.
(picking is a kind of choosing)
'finest editor' is the wordplay.
'finest' becomes 'pick' (as in 'take your pick').
'editor' becomes 'ed'.
'pick'+'ed'='PICKED'
(Other definitions for picked that I've seen before include "Selected or unlocked with a wire" , "Chosen" , "Chose" .)