Receptive earlier, after energy up slightly (8)

I believe the answer is:

pervious

'receptive' is the definition.
('pervious' can be similar in meaning to 'receptive')

'earlier after energy up slightly' is the wordplay.
I cannot quite see how this works, but
'energy' could be 'pe' (P.E. is an example) and 'pe' is located in the answer.
This explanation may well be incorrect...

I've seen this clue in The Guardian.

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