Slacker and no-hoper accepting Oscar (6)
I believe the answer is:
looser
'slacker' is the definition.
('loose' can be a synonym of 'slack')
'no-hoper accepting oscar' is the wordplay.
'no-hoper' becomes 'loser' (I've seen this before).
'accepting' is an insertion indicator.
'oscar' becomes 'O' (phonetic alphabet: alpha, bravo, charlie etc.).
'loser' going around 'o' is 'LOOSER'.
'and' is the link.
(Other definitions for looser that I've seen before include "less secure" , "Rather inaccurate" .)