red flag vs irritation

red flag and irritation both are nouns.

Word	Noun	Adjective	Verb	Adverb
red flag	Yes	No	No	No
irritation	Yes	No	No	No

As nouns, irritation is a hypernym of red flag; that is, irritation is a word with a broader meaning than red flag:

Other hypernyms of red flag include annoyance, annoying, vexation.

red flag (noun)	irritation (noun)
something that irritates or demands immediate action	unfriendly behavior that causes anger or resentment
a flag that serves as a warning signal	the act of troubling or annoying someone
the emblem of socialist revolution	an uncomfortable feeling of mental painfulness or distress
	a sudden outburst of anger
	the psychological state of being irritated or annoyed
	the neural or electrical arousal of an organ or muscle or gland
	(pathology) abnormal sensitivity to stimulation