Danny DeVito sitcom (4)
I believe the answer is:
'danny devito sitcom' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for taxi that I've seen before include "Danny DeVito sitcom" , "move on ground before take-off" , "At airport, guide" , "Part of fleet" , "(Of a plane) move slowly on the ground" .)