Unusual foresight - avoid an oral examination here (4,5)
I believe the answer is:
gift horse
'avoid an oral examination here' is the definition.
(ref to 'don't look a gift horse in the mouth')
'unusual foresight' is the wordplay.
'unusual' indicates an anagram.
'foresight' with letters rearranged gives 'GIFT HORSE'.
(Other definitions for gift horse that I've seen before include "Chance benefit (oral exam not recommended!)" , "Don't look one in the mouth" , "Trojan present?" , "'Never look a . . . . . . . . . in the mouth'" , "Hack, perhaps, given" .)