Spring in field leading to first pond (4)
I believe the answer is:
leap
'spring' is the definition.
('leap' can be a synonym of 'spring')
'field leading to first pond' is the wordplay.
'field' becomes 'lea' (I've seen this before).
'leading to' means one lot of letters go next to another (some letters go before or lead others).
'first' says to take the initial letters.
The initial letter of 'pond' is 'p'.
'lea'+'p'='LEAP'
'in' is the link.
(Other definitions for leap that I've seen before include "vault" , "'Look before you . . . .'" , "Spring suddenly" , "Basket" , "Pounce" .)