big-girl pants

Noun

big-girl pants pl (plural only)

1. (informal, plural, plural-only) Pull-up underwear worn by a girl during and after toilet training, as contrasted to the diapers worn during infancy.
   • Talk about how she'll be able to wear big-girl pants or fancy pants (decorated training pants) because she will learn to use the potty.1987, Stephen W. Garber, Good Behavior: Over 1,200 Sensible Solutions to Your Child's Problems from Birth to Age Twelve, Villard Books, published 1987, →ISBN, page 161
   • You might say something like, “Nancy, this morning before you woke up, Dolly went pee-pee in her big-girl pants. We don't go pee-pee in our big-girl pants, do we?”2006, Teri Crane, Potty Train Your Child in Just One Day: Proven Secrets of the Potty Pro, Fireside, published 2006, →ISBN, page 240
2. (figuratively, informal, plural, plural-only) A notional pair of trousers or underwear worn by a female when acting maturely.
   • I am very disappointed, but we did always say we wanted the best dog for her, so I will have to put my big girl pants on now and have faith that this will be the perfect dog for our family and for Ehlena.2010, Stacy Fry, “Hope for Independence: A Diary Excerpt”, in Kathy Nimmer, editor, Two Plus Four Equals: Celebrating the Partnership of People with Disabilities and Their Assistance Dogs, Dog Ear...
   • So put on your big-girl pants and own up to what you and your stupidity caused.2011, Sherrilyn Kenyon, Retribution, St. Martin's Press, published 2011, →ISBN, page 95

   Antonyms:

   bitchy pants, grumpy pants, scaredy pants