Meaning of “smear” - Learner’s Dictionary

smear

verb [ T ] uk us /smɪər/
SPREAD

to spread a thick liquid or sticky substance over something:

His shirt was smeared with paint.
He smeared sun cream over his face and neck.
SAY

to say unpleasant and untrue things about someone in order to harm them, especially in politics

(Definition of “smear verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)