Low way of working on an inside job (3)
I believe the answer is:
moo
'low' is the definition.
(I've seen this before)
'way of working on an inside job' is the wordplay.
'way of working' becomes 'mo' (I've seen this in other clues).
'on' says to put letters next to each other.
'an inside' says to take the centre.
The centre of 'job' is 'o'.
'mo'+'o'='MOO'
(Other definitions for moo that I've seen before include "Farmyard sound" , "Cartoon sound of a cow" , "Cow's sound" , "unpopular woman" , "Cow's call" .)