In the open air, beat gold (7)
I believe the answer is:
outdoor
'in the open air' is the definition.
(I've seen this before)
'beat gold' is the wordplay.
'beat' becomes 'outdo' (outdoing is a kind of beating).
'gold' becomes 'or' ('or' is the heraldic name for gold).
'outdo'+'or'='OUTDOOR'
(Other definitions for outdoor that I've seen before include "Located in the open air" , "exposed to the elements" , "Al fresco" , "Done in the open" , "healthy pursuits" .)