The Open Dictionary

dobber

noun

UK/ˈdɒb.əʳ/
US/ˈdɑː.bɚ/

Definitions of dobber noun

  1. Countable

    A person who secretly informs a person of authority about someone else's wrongdoings.

    • He was seen as a dobber by his classmates for telling the teacher about the cheating.

    • She never acts as a dobber at work, always addressing issues directly with colleagues.

    • The manager was seen as a dobber for criticizing his staff to the boss behind their backs.