Notice nothing to cause fuss (3)
I believe the answer is:
ado
'fuss' is the definition.
(synonyms)
'notice nothing' is the wordplay.
'notice' becomes 'ad' (both can mean an advertisement).
'nothing' becomes 'o' (looks like zero - 0).
'ad'+'o'='ADO'
'to cause' is the link.
(Other definitions for ado that I've seen before include "Hoo-ha" , "Fuss, trouble" , "flapping" , "hoo-hah" , "'Much ... About Nothing, Shakespeare play (3)'" .)