One look may be child's-play (1-3)
I believe the answer is:
i-spy
'be child's-play' is the definition.
I can't tell whether this definition defines the answer.
'one look' is the wordplay.
I cannot quite see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'look' could be 'spy' (spy can mean to look or see) and 'spy' is found within the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'may' acts as a link.
Can you help me to learn more?
(Other definitions for i-spy that I've seen before include ". ... with my little eye (children's game)" , "Wordgame" , "Child's guessing game" , "Game played with young children" , "Child's game: ''. ... with my little eye'" .)