Wallis Warfield Windsor vs grass widow

Wallis Warfield Windsor and grass widow both are nouns.

Word	Noun	Adjective	Verb	Adverb
Wallis Warfield Windsor	Yes	No	No	No
grass widow	Yes	No	No	No

Wallis Warfield Windsor (noun)	grass widow (noun)
United States divorcee whose marriage to Edward VIII created a constitutional crisis leading to his abdication	a divorced woman or a woman who is separated from her husband