Vehicle endlessly crowded? (3)
I believe the answer is:
bus
'vehicle' is the definition.
(bus is a kind of vehicle)
'endlessly crowded?' is the wordplay.
'endlessly' means to remove the last letter.
'crowded?' becomes 'busy' (I've seen this before).
'busy' with its last letter taken off is 'BUS'.
(Other definitions for bus that I've seen before include "Public transport vehicle" , "People carrier" , "Large passenger vehicle - small business!" , "Coach" , "Public service vehicle" .)