The story
From big boy.
Etymology from Wiktionary, CC BY-SA 4.0.
big-boy pants
Today it means: Pull-up underwear worn by a boy during and after toilet training, as contrasted to the diapers worn during infancy. Full definition →
Today it means: Pull-up underwear worn by a boy during and after toilet training, as contrasted to the diapers worn during infancy. Full definition →
From big boy.
Etymology from Wiktionary, CC BY-SA 4.0.