Quench thirst from small pond (5)
I believe the answer is:
slake
'quench thirst' is the definition.
'small pond' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'pond' becomes 'lake' (I have seen 'Large pond ' mean 'lake' so perhaps 'pond' could also mean 'lake').
's'+'lake'='SLAKE'
'from' acts as a link.
(Other definitions for slake that I've seen before include "Quench (one's thirst)" , "Satisfy one's thirst" , "Assuage" .)