Grass boosting energy? Hardly (6)
I believe the answer is:
barely
'hardly' is the definition.
(I know that hardly can be written as barely)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for barely that I've seen before include "Not quite" , "how babies are born?" , "Just about or scantily" , "how naturists exist" , "how streakers like to act?" .)