Praise a double somersault (4)
I believe the answer is:
laud
'praise' is the definition.
(I know that laud is a more specific form of the action praise)
'a double somersault' is the wordplay.
'a double' becomes 'dual' (I've seen this in another clue).
'somersault' shows that the letters should be reversed in order.
'dual' reversed gives 'LAUD'.
(Other definitions for laud that I've seen before include "Praise acclaim" , "'Praise, glorify (4)'" , "Praise highly" , "Praise - celebrate" , "Name of archbishop; praise" .)