利害
りがい · rigai · JLPT N2 · noun
disadvantage
利 — grain 禾 + knife 刂
Originally a pictograph showing a knife (刂) cutting grain (禾), depicting harvest. From the idea of a sharp blade reaping crops, it extended to mean 'sharp,' then 'benefit,' 'profit,' or 'advantage' — the gain that comes from a successful harvest.
害 — 宀 roof + 丯 (phonetic) + 口 mouth
Originally an ideograph showing harm spoken under a roof, with 宀 (roof/house) on top, a phonetic element 丯 in the middle, and 口 (mouth) below suggesting harmful speech. Over time it shifted from 'injury caused by words' to the broader senses of 'harm,' 'injure,' and 'fear.'