Fair appeal leading to duck (2-2)
I believe the answer is:
so-so
'fair' is the definition.
(I've seen this before)
'appeal leading to duck' is the wordplay.
'appeal' becomes 'sos' (I have seen 'urgent appeal' mean 'sos' so perhaps 'appeal' could also mean 'sos').
'leading to' means one lot of letters go next to another (some letters go before or lead others).
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'sos'+'o'='SO-SO'
(Other definitions for so-so that I've seen before include "Mediocre" , "just about adequate" , "Of average quality" , "Fair to middling" , "'Passable, middling (2-2)'" .)