white flag vs flag of truce

white flag and flag of truce both are nouns.

Word	Noun	Adjective	Verb	Adverb
white flag	Yes	No	No	No
flag of truce	Yes	No	No	No

As nouns, white flag and flag of truce are synonyms defined as:

white flag and flag of truce: flag consisting of a piece of white cloth that is hoisted to signal surrender or to ask for a truce

white flag (noun)	flag of truce (noun)
flag consisting of a piece of white cloth that is hoisted to signal surrender or to ask for a truce	flag consisting of a piece of white cloth that is hoisted to signal surrender or to ask for a truce