A child, usually but not limited to three years of age or younger, who feels the need to scream at the top of their lungs any time they're in a large store, usually a Walmart, and expecially when they don't get something.
"My sister was a Walmart Wailer. That's why my mom had to beg me to go to the store."

*child screaming in the same isle as you, making a chain reaction from all of the children in the store*
"OMG I WISH THEY WOULD SHUT UP THEIR WALMART WAILERS ALREADY!!"
by AWWAleader September 2, 2011
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