Give in! It's almost time to take the bus back (6)
I believe the answer is:
submit
'give in' is the definition.
(submitting is a kind of giving in)
'almost time to take the bus back' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'to take' is a charade indicator (letters next to each other).
'back' is a reversal indicator.
'time' with its last letter removed is 'tim'.
'tim'+'bus'='timbus'
'timbus' reversed gives 'SUBMIT'.
'it's' acts as a link.
(Other definitions for submit that I've seen before include "Give way" , "Give in to another's wishes" , "Consent" , "Yield (to superior force)" , "Defer, give in" .)