Farewell notice that is for all to see (5)
I believe the answer is:
adieu
'farewell' is the definition.
(adieu is a kind of farewell)
'notice that is for all to see' is the wordplay.
'notice' becomes 'ad'.
'that is' becomes 'ie' ('i.e.' can be a synonym of 'that is').
'for all to see' becomes 'u' (universal dvd certificate).
'ad'+'ie'+'u'='ADIEU'
(Other definitions for adieu that I've seen before include "Bye" , "Gallic goodbye" , "12 Down" , "cheers" , "Parting word" .)