Transport of tautological interpretation (4)
I believe the answer is:
auto
'transport' is the definition.
(auto is a kind of transport)
'of tautological interpretation' is the wordplay.
'of' indicates the answer is hidden within the clue.
'AUTO' can be found hidden inside 'tautological interpretation'.
(Other definitions for auto that I've seen before include "American vehicle" , "Lincoln?" , "Prefix to denote self or same" , "Car (mostly US)" , "Drama" .)