Antonyms of noun faithfulness

1 sense of faithfulness

Sense 1
fidelity, faithfulness -- (the quality of being faithful)
       Antonym of unfaithfulness (Sense 1)
      => infidelity, unfaithfulness -- (the quality of being unfaithful)

Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun faithfulness

1 sense of faithfulness

Sense 1
fidelity, faithfulness -- (the quality of being faithful)
       => quality -- (an essential and distinguishing attribute of something or someone; "the quality of mercy is not strained"--Shakespeare)