Super increase (5)
I believe the answer is:
swell
I believe this clue is a double definition.
'super' is the first definition.
(thesaurus)
'increase' is the second definition.
(swelling is a kind of increasing)
(Other definitions for swell that I've seen before include "Movement of the surface of the sea" , "'Increase in size, number etc (5)'" , "Expand - big wig" , "Distend" , "Bulge; a nob" .)