Lets cats run amok, which is insensitive (8)
I believe the answer is:
tactless
'is insensitive' is the definition.
(I've seen this before)
'lets cats run amok' is the wordplay.
'run amok' indicates an anagram.
'lets'+'cats'='letscats'
'letscats' anagrammed gives 'TACTLESS'.
'which' acts as a link.
(Other definitions for tactless that I've seen before include "Undiplomatic" , "Lacking skill in handling delicate situations" , "Unlikely to make Diplomatic Service" , "Lacking sensitivity, saying the wrong things" , "Lacking consideration" .)