Suru verb, Noun, Adverb (fukushi), Adverb taking the 'to' particle, Intransitive verb
to get irritated; to get annoyed; to be on the edge; to fret; to lose patience
Usually written using kana aloneOnomatopoeic or mimetic word
ビルは試験のことでいらいらしている。Bill is nervous about the exam.
Also written 苛苛【いらいら】、刺々【いらいら】、刺刺【いらいら】