cootie

plural cooties

1. British ArmyCanadaUScolloquialdatedslanggovernmentA louse (Pediculus humanus).

   1 more example

   "Tell Rilla I'm glad her war-baby is turning out so well, and tell Susan that I'm fighting a good fight against both Huns and cooties." "Mrs. Dr. dear," whispered Susan solemnly, "what are cooties?" Mrs. Blythe whispered back and then said in reply to Susan's horrified ejaculations, "It's always like that in the trenches, Susan." Susan shook her head and went away in grim silence to re-open a parcel she had sewed up for Jem and slip in a fine tooth comb.

   1921, L. M. Montgomery, Rilla of Ingleside

2. AustraliaCanadaUSchildishcolloquialplural normallyAny germ or contaminant, real or imagined, especially from the opposite gender (for pre-pubescent children).

   I’m not drinking from his glass until I wash the cooties off it.

   1 more example

   I asked them why they had separated themselves from one another so dramatically. One tiny girl, sitting up straight so she wouldn’t bump into the two large boys on either side of her, said matter-of-factly, “We found out that boys have cooties!” There was a chorus of assent from the other girls. ”Girls have cooties too!” the boys yelled, not to be outdone.

   2001, Michael Thompson, Ph.D., and Catherine O’Neill Grace with Lawrence J. Cohen, Ph.D., Best Friends, Worst Enemies: Understanding the Social Lives of Children

3. rareA nest-building female American coot (counterpart to cooter).
4. rareslangA sideswiper, a type of telegraph key.