Sentence:  Ay, that incestuous, that <WSD>adulterate</WSD> beast, / With witchcraft of his wit, with traitorous gifts- / O wicked wit and gifts, that have the power / So to seduce!- won to his shameful lust / The will of my most seeming-virtuous queen. 
Meaning of the word marked with <WSD> tags:  Tending to commit adultery.