Sentence:  The Sea-king, Ravisher of Ilium / Knows not her false and slavering tongue, thrust out, / Lewd bitch, to lick and fawn and smile and be / The secret soul of unforgiving hell! / Dare it, She-devil! <WSD>Unsex</WSD> thyself, and be His murderess! 
Meaning of the word marked with <WSD> tags:  To deprive of sexual attributes or characteristics.