Quiz expert about point obliquely (7)
I believe the answer is:
askance
'obliquely' is the definition.
(I've seen this before)
'quiz expert about point' is the wordplay.
'quiz' becomes 'ask' (quiz can mean to ask a question).
'expert' becomes 'ace' (ace can informally mean very good).
'about' means one lot of letters goes inside another.
'point' becomes 'n' (N is an example).
'ace' placed around 'n' is 'ance'.
'ask'+'ance'='ASKANCE'
(Other definitions for askance that I've seen before include "Look this way in doubt or suspicion" , "In suspicious manner" , "Look thus to regard with distrust" , "Obliquely, quizzically" , "Suspiciously, with disfavour" .)