This isn’t the reading you learned with the kanji, so here's a mnemonic to help you:
You don’t just get irritated, you get ira-ira-tated (いらいら). That's the next level up from irritated.
This word is often written in katakana or hiragana, but you'll sometimes see it in kanji too, so it's worth knowing!
That person is always irritated, huh?
Don't get impatient while you're driving.
It's not like I’m trying to get annoyed.