Definition of clown car:
(n) :
(by extension, often derogatory) A very small car.
(n) :
(comedy) A circus clown routine in which an implausibly large number of clowns climb into or out of a small car.
(n) :
The undersized car used in a circus clown car routine.
(n) :
(by extension) A car or small enclosed space with too many people or things in it.
(n) :
(figurative, derogatory, often politics) Any process with a comically large number of participants, especially participants who themselves are comical or ridiculous.
(n) :
(literally) A car for clowns, especially the car of a circus train that carries the clowns.