Advertisement for "The Laggard" (7)
I believe the answer is:
trailer
I believe this is a double definition.
'advertisement' is the first definition.
(I know that trailer is a type of advertisement)
'laggard' is the second definition.
(I know that laggard can be written as trailer)
'for the' is the link.
(Other definitions for trailer that I've seen before include "It's pulled by a vehicle" , "Creeping plant" , "ground plant" , "Short film advertising a forthcoming feature" , "Vehicle designed to be towed by another" .)