恨うらみっこ

noun

hard feelings; mutual resentment

Almost always used in negative constructions like 恨みっこなし or 恨みっこなしだよ, meaning 'no hard feelings' or 'let's not hold grudges'. A casual, somewhat childish word.

• 負まけても恨うらみっこなしだよ。

  No hard feelings even if you lose.

• お互たがいさま、恨うらみっこなしにしよう。

  It's mutual, so let's not hold any grudges.