Break out of revolutionary clean environment at last (5)
I believe the answer is:
erupt
'break out' is the definition.
(synonyms)
'revolutionary clean environment at last' is the wordplay.
'revolutionary' says the letters should be written in reverse (letters revolve around).
'clean' becomes 'pure' (similar in meaning).
'at last' indicates one should take the final letters.
The final letter of 'environment' is 't'.
'pure' written backwards gives 'erup'.
'erup'+'t'='ERUPT'
'of' is the link.
(Other definitions for erupt that I've seen before include "Break through (as a volcano)" , "Discharge" , "Explode" , "Suddenly appear" , "go up" .)