Crossword Genius

With one again in the old environment (6)

Ross

I believe the answer is:

agreed

I'm a little stuck... Click here to teach me more about this clue!

'with one' is the definition.
Both the answer and definition are adjectives. Perhaps there's a link between them I don't understand?

'again in the old environment' is the wordplay.
I cannot quite see how this works, but
'again' could be 're' (prefix meaning 'again') and 're' is found within the answer.
'old' could be 'aged' (similar in meaning) and 'aged' is present in the leftover letters.
No letters remain.
This may be the basis of clue (or it may be nonsense).

Can you help me to learn more?

(Other definitions for agreed that I've seen before include "Acceded" , "Let's do it!" , "Was consistent" , "It's a deal!" , "Consented and concurred" .)

I've seen this clue in the Evening Standard.
Want a hint initially instead of a full solution? Install my app