child's play

child's play idiom
Something easily done, a trivial matter. For example, Finding the answer was child's play for Robert, or The fight we had was child's play compared to the one I had with my mother! Originating in the early 1300s as child's game, the idiom was already used in its present form by Chaucer in The Merchant's Tale: “It is no child's play to take a wife.”

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

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