From Longman Dictionary of Contemporary Englishirritantir‧ri‧tant /ˈɪrɪtənt/ noun [countable] 1 ANNOY formal something that keeps annoying you over a period of time Low-flying aircraft are a constant irritant in this area.2 MIHURT/CAUSE PAINa substance that can make a part of your body painful and sore a skin irritant
Examples from the Corpus
irritant• My fatigue and this added irritant started to push me into a depression.• One of these involves using the hind leg to scratch an area of skin to which an irritant has been applied.• In this plant was a milky substance which was a drastic purge and irritant.• There are few worse irritants for eyes and hand cuts. 