Good rate revised: fantastic! (5)
I believe the answer is:
great
'fantastic' is the definition.
(fantastic can mean great or excellent)
'good rate revised' is the wordplay.
'good' becomes 'g' (abbreviation).
'revised' is an anagram indicator.
'rate' is an anagram of 'reat'.
'g'+'reat'='GREAT'
(Other definitions for great that I've seen before include "Peter the -, Russ. tsar" , "Important; immense" , "1963 Buckinghamshire mail van raid" , "Waterbird" , "Enormous" .)