Child's play Meaning, Definition & Usage

1. noun any undertaking that is easy to do
   picnic; walkover; duck soup; piece of cake; breeze; cinch; snap; pushover.
   
   • marketing this product will be no picnic
2. noun activity by children that is guided more by imagination than by fixed rules
   play.
   
   • Freud believed in the utility of play to a small child

WordNet