Definition of "undie"

undie¹

/ˈʌndi/

noun
plural undies
1. (informal, often attributive) Underwear.
  Quotations
  Here are a few pointers from an undie-snatching master.
  1999 November, Derek de Koff, "Portrait of a Fetishist", Out, page 70
  Add an undie stop to the list.
  2004 November, Lian Dolan, "Chaos Chronicles", Working Mother, page 98
  Pick up the baby’s vest off the floor and put it on as an undie.
  2006, Upamanyu Chatterjee, Weight Loss, page 348

undie²

/ˈʌndi/

noun
plural undies
1. (informal) A spy, undercover agent.
  Quotations
  I've got mad hate for the undiesMoving like gyal, tryna cuff me
  2016, “Let’s Lurk”, ASAP (lyrics), performed by 67 ft Giggs
  Got a mind for the undiesI'm tryna stay far from the pigs
  2017, “All This”, performed by Mayhem (Uptop)

undie³

/ʌnˈdaɪ̯/

verb
third-person singular simple present undies, present participle undying, simple past and past participle undied
1. (intransitive) To come back to life after having died.
2. (intransitive) To become undead.