tattletale

/ˈtætəlˌteɪl/
noun
  1. A person, especially a child, who tells an authority figure about someone else's wrongdoing, often to get them in trouble.
    • The other kids refused to play with the tattletale who ran to the teacher every five minutes.
    • In the story, the tattletale mouse warned the farmer about the fox every time.
    • My little brother is such a tattletale — he told Mom I didn't do my homework.
adjective
  1. Revealing information or secrets; telling on someone.
    • The tattletale paint color showed every fingerprint on the wall.
    • The dog's tattletale barking alerted us that someone was at the door.
    • Her tattletale expression gave away the surprise party plans.
What does "tattletale" mean? | whatsthatwordmean | whatsthatwordmean