About due to finish, to spill a pint is useless (5)
I believe the answer is:
inept
'useless' is the definition.
(thesaurus)
'about due to finish to spill a pint' is the wordplay.
'about' means one lot of letters goes inside another.
'to finish' suggests the final letters.
'to spill' is an anagram indicator.
The last letter of 'due' is 'e'.
'pint' is an anagram of 'inpt'.
'e' going into 'inpt' is 'INEPT'.
'is' acts as a link.
(Other definitions for inept that I've seen before include "Hopeless; bungling" , "Foolish" , "Clumsy, bungling" , "Incompetent and ineffectual" , "Awkward, showing no skill" .)