Intense — sharp (8)
I believe the answer is:
piercing
I believe this is a double definition.
'intense' is the first definition.
(thesaurus)
'sharp' is the second definition.
(I know that sharp can be written as piercing)
(Other definitions for piercing that I've seen before include "very loud" , "Shrill" , "Making a hole in (something)" , "Very cold (wind)" , "Ear-splitting" .)