I am to get minimal marks, test being wicked (7)
I believe the answer is:
immoral
'wicked' is the definition.
('immoral' can be similar in meaning to 'wicked')
'i am to get minimal marks test' is the wordplay.
'i am' becomes 'im'.
'to get' is a charade indicator (letters next to each other).
'minimal' says to take the initial letters.
'test' becomes 'oral' (oral is a type of examination).
The initial letter of 'marks' is 'm'.
'im'+'m'+'oral'='IMMORAL'
'being' acts as a link.
(Other definitions for immoral that I've seen before include "involved in depravity?" , "bad!" , "Violating accepted principles of right and wrong" , "Ignoring right and wrong" , "Corrupt - dissolute" .)