More active (6)
I believe the answer is:
busier
'more active' is the definition.
('busy' can be similar in meaning to 'active')
This is the entire clue.
(Other definitions for busier that I've seen before include "More fully engaged in work" , "More fully engaged or occupied" , "Having a great deal more to do" , "More active or engaged in work" , "More full of activity" .)