Predator catching egg layer (4)
I believe the answer is:
coat
'layer' is the definition.
(I have seen 'Layer of paint' mean 'coat' so perhaps 'layer' could also mean 'coat')
'predator catching egg' is the wordplay.
'predator' becomes 'cat' (cats are predators).
'catching' indicates putting letters inside.
'egg' becomes 'o' (an 'o' resembles an egg).
'cat' placed around 'o' is 'COAT'.
(Other definitions for coat that I've seen before include "Jacket" , "Layer of paint" , "Apply layer" , "Outer garment" , "Fleece" .)