Fail to keep up in time? Wretched! (8)
I believe the answer is:
desolate
'wretched' is the definition.
(I've seen this before)
'fail to keep up in time?' is the wordplay.
'fail to keep' becomes 'lose' ('lose' can be a synonym of 'fail to keep').
'up' says the letters should be written backwards (in down clue: letters go upwards).
'in' means one lot of letters goes inside another.
'time?' becomes 'date' (date is a kind of time).
'lose' reversed gives 'esol'.
'esol' put inside 'date' is 'DESOLATE'.
(Other definitions for desolate that I've seen before include "'Bleak, bare (8)'" , "Bereft" , "Lay waste, despoil" , "Crushed by grief" , "alone" .)