Sentence:  Villain, be sure thou prove my love a whore, / Be sure of it; give me the <WSD>ocular</WSD> proof: / Or by the worth of man's eternal soul, / Thou hadst been better have been born a dog / Than answer my waked wrath! 
Meaning of the word marked with <WSD> tags:  Seen by, or seeing with, the eye; visual.