Not be able to arrange a date, alas? (8)
I believe the answer is:
lackaday
'alas?' is the definition.
(I've seen this before)
'not be able to arrange a date' is the wordplay.
I cannot really see how this works, but
'a' is within the answer.
'date' could be 'day' (I have seen 'Particular date' mean 'day' so perhaps 'date' could also mean 'day') and 'day' is found within the answer.
This explanation may well be incorrect...
(Other definitions for lackaday that I've seen before include "cry of dismay" , "alas" , "How sad" , "unfortunately" .)