irritable vs testy

irritable and testy both are adjectives.

Word	Noun	Adjective	Verb	Adverb
irritable	No	Yes	No	No
testy	No	Yes	No	No

As adjectives, irritable and testy are synonyms defined as:

Other synonyms of irritable include cranky, fractious, nettlesome, peckish, peevish, pettish, petulant, scratchy, techy, tetchy.

irritable (adjective)	testy (adjective)
easily irritated or annoyed	easily irritated or annoyed
capable of responding to stimuli
abnormally sensitive to a stimulus