It's sort of very loud and strong (5)
I believe the answer is:
stiff
'strong' is the definition.
(I know that strong can be written as stiff)
'it's sort of very loud' is the wordplay.
'sort of' is an anagram indicator.
'very loud' becomes 'ff' (musical abbreviation for 'fortissimo', very loud).
'its' with letters rearranged gives 'sti'.
'sti'+'ff'='STIFF'
'and' is the link.
(Other definitions for stiff that I've seen before include "Not easily bent" , "18 [HARD]" , "Difficult" , "tough" , "Not giving" .)