New exotic pen in special case (9)
I believe the answer is:
exception
'special case' is the definition.
(I've seen this before)
'new exotic pen' is the wordplay.
'new' is an anagram indicator.
'exotic'+'pen'='exoticpen'
'exoticpen' is an anagram of 'EXCEPTION'.
'in' acts as a link.
(Other definitions for exception that I've seen before include "Something that does not follow the rule" , "It's said to prove a rule" , "that may be taken as an offence" , "Omission" , "It may be taken after a slight" .)