Pi cousin’s somehow causing scepticism! (9)
I believe the answer is:
suspicion
'scepticism' is the definition.
(I've seen this before)
'pi cousin's somehow' is the wordplay.
'somehow' is an anagram indicator.
'pi'+'cousins'='picousins'
'picousins' with letters rearranged gives 'SUSPICION'.
'causing' is the link.
(Other definitions for suspicion that I've seen before include "Suggestion" , "Hitchcock classic" , "Hunch" , "Hitchcock film" , "Trace" .)