Something easy to do (1,4,2,3,4)
I think it could be either:
a walk in the park
'something easy to do' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for a walk in the park that I've seen before include "enjoyed by the setter?" , "passing through Tivoli Gardens?" , "A piece of cake" , "Plain Sailing'" , "A breeze" .)
(Other definitions for childs play that I've seen before include "Peter Pan, say, on stage" , "A doddle" , "simple task" , "no problem" , "Something very easy to do" .)