Grey Friar vs friar

Grey Friar and friar both are nouns.

Word	Noun	Adjective	Verb	Adverb
Grey Friar	Yes	No	No	No
friar	Yes	No	No	No

As nouns, friar is a hypernym of Grey Friar; that is, friar is a word with a broader meaning than Grey Friar:

Grey Friar: a Roman Catholic friar wearing the grey habit of the Franciscan order
friar: a male member of a religious order that originally relied solely on alms

Other hypernyms of Grey Friar include mendicant.

Grey Friar (noun)	friar (noun)
a Roman Catholic friar wearing the grey habit of the Franciscan order	a male member of a religious order that originally relied solely on alms