Best definition
walmart ass
A human being with an ass that takes up the whole aisle at walmart.
Also has many dynamic features to it.

walmart ass: define #2
walmart ass
A woman with a shelf like rear end known to shop at walmart.
That lady a walmart ass so big she has to go through doors sideways.
walmart ass: define #3
walmart ass
When you can’t make it to the mall where the hot chicks hang out, you are relegated to Wal Mart. Where you check out the lower grade, but sometimes fine pieces of ass that are shopping there.
Everytime I go to Wal Mart I always see some good walmart ass.