A burr or husk (e.g., the spiky casing of a chestnut) — a noun referring to a spiny, burr‑like object.
道ばたに落ちている栗のイガイガを踏まないよう気をつけてください。
Be careful not to step on the chestnut burrs lying by the roadside.
犬が庭でイガイガを咥えてきた。
The dog picked up a burr in its mouth from the yard.
An onomatopoeic adverb describing an irritating, scratchy sensation (often in the throat) — used as 'いがいがする' or with the particle 'と'.
風邪で喉がいがいがして、声が出にくい。
My throat feels scratchy from a cold, and it's hard to speak.
冷たい風を浴びて、胸がいがいがと痛んだ。
After being in the cold wind, my chest ached with a prickly sensation.
煙草の煙で喉がいがいがすることがある。
Cigarette smoke can sometimes make the throat feel scratchy.
An archaic onomatopoeia representing a baby's crying (historical usage).
昔の日記には『いがいがと夜泣きする』と書かれていることがある。
Old diaries sometimes record phrases like 'igai‑ga to yonaki suru' (the baby cried at night).