Wading bird initially enjoying good soak (5)
I believe the answer is:
egret
'wading bird' is the definition.
(egret is a kind of wading bird)
'initially enjoying good soak' is the wordplay.
'initially' indicates taking the first letters.
'soak' becomes 'ret' (ret can mean to soak in water).
The first letters of 'enjoying good' is 'eg'.
'eg'+'ret'='EGRET'
(Other definitions for egret that I've seen before include "Bird eating fish" , "white fish eater" , "Long-plumed heron" , "White-plumed wader" , "one with plume" .)