Cab charge beginning to irritate (4)
I believe the answer is:
taxi
'cab' is the definition.
(taxi cab)
'charge beginning to irritate' is the wordplay.
'charge' becomes 'tax' (tax is a kind of charge).
'beginning to' says to take the initial letters.
The first letter of 'irritate' is 'i'.
'tax'+'i'='TAXI'
(Other definitions for taxi that I've seen before include "Rank occupant" , "Danny DeVito sitcom" , "(Of a plane) move slowly on the ground" , "Car for hire" , "Hackney cab" .)