Dated polite term, historically associated with feminine speech. Now rarely used; modern equivalents include お手洗い or トイレ.
I hear that women in the past used to say, 'I will go to the bathroom.'
Standard spelling with honorific prefix ご.
Variant with kanji honorific prefix 御; less common than ご不浄.
Compound of honorific prefix ご and 不浄 (impurity, uncleanliness), literally 'honorable unclean place', a euphemism for toilet.