Definition of "undies"

undies¹

noun
plural only
1. (informal) underwear, underpants
  Quotations
  I hope so because I can't wear the suit without the shirt. I went to go look in my dresser. I found it and got out my undies and socks.
  2004, T. Fulton, Da Joka: Frisco’s Finest, page 59

undies²

verb
1. third-person singular simple present indicative of undie