Opposites may be pointed out in a second (9)
I believe the answer is:
antipodes
'opposites' is the definition.
(I have seen 'Exact opposites' mean 'antipodes' so perhaps 'opposites' could also mean 'antipodes')
'pointed out in a second' is the wordplay.
'out' indicates an anagram (out can mean wrong or inaccurate).
'in' means one lot of letters goes inside another.
'second' becomes 's' (common abbreviation).
'pointed' with letters rearranged gives 'ntipode'.
'a'+'s'='as'
'ntipode' going inside 'as' is 'ANTIPODES'.
'may be' acts as a link.
(Other definitions for antipodes that I've seen before include "most clocks here show the same time" , "Places that are on opposite sides of the world" , "Diametrically opposite location" , "Exact opposites" , "The other side of the world" .)