Extreme, severe (7)
I believe the answer is:
drastic
This clue is a double definition.
'extreme' is the first definition.
(I've seen this before)
'severe' is the second definition.
(I've seen this before)
(Other definitions for drastic that I've seen before include "Unsparing" , "Extreme - forceful" , "Desperate" , "Radical, extreme" , "Radical, far-reaching" .)