Definition of behinds:
(adv) :
At or in the rear or back part of something.
(adv) :
So as to come after someone or something in position, distance, advancement, ranking, time, etc.
(adv) :
In a rearward direction.
(adv) :
Backward in time or order of succession; past.
(adv) :
So as to be still in place after someone or something has departed or ceased to exist.
(adj) :
Not advanced to the required or expected degree; overdue or in arrears.