Excellent energy party picked up (4)
I believe the answer is:
good
'excellent' is the definition.
(thesaurus)
'energy party picked up' is the wordplay.
'energy' becomes 'go' (I've seen this in other clues).
'party' becomes 'do' (do is a kind of party).
'picked up' is a reversal indicator.
'do' back-to-front is 'od'.
'go'+'od'='GOOD'
(Other definitions for good that I've seen before include "Of a high standard" , "Well done! Health-giving" , "Priestley's companions" , "Fine" , "Enjoyable -- moral" .)