Typically badly peeled navel orange (2,7)
I believe the answer is:
on average
'typically' is the definition.
(I've seen this before)
'badly peeled navel orange' is the wordplay.
'badly' indicates an anagram (letters in the wrong order).
'peeled' says to take the centre (outer letters are peeled off).
The centre of 'navel' is 'ave'.
'ave'+'orange'='aveorange'
'aveorange' anagrammed gives 'ON AVERAGE'.
(Other definitions for on average that I've seen before include "Usually" , "Generally" , "typically speaking" .)