Definition of "equivocator"

Knock. Knock, knock. Who's there in th'other Deuils Name? Faith here's an Equiuocator, that could ſweare in both the Scales againſt eyther Scale, who committed Treaſon enough for Gods ſake, yet could not equiuocate to Heauen: oh come in, Equiuocator.

c. 1606 (date written), William Shakespeare, “The Tragedie of Macbeth”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene iii], page 137, column 1