a.
1.
Faithless, knavish, false, unfair, disingenuous, fraudulent, deceitful, treacherous, slippery, unscrupulous, perfidious, false-hearted, without probity, destitute of integrity.
2.
[ Said of women .] Unchaste, unvirtuous, wanton, lewd, unfaithful ( to marriage vows ).