It's not clear that Victor has a complaint (5)
I believe the answer is:
vague
'it's not clear' is the definition.
(I know that vague is the opposite attribute of clear)
'victor has a complaint' is the wordplay.
'victor' becomes 'V' (phonetic alphabet: alpha, bravo, charlie etc.).
'has' means one lot of letters go next to another.
'a complaint' becomes 'ague' (ague is a kind of disease).
'v'+'ague'='VAGUE'
'that' acts as a link.
(Other definitions for vague that I've seen before include "Indefinite" , "Indistinct or imprecise" , "Obscure, undefined" , "Indeterminate" , "Inexact" .)