遺恨[ikon] grudge
怨恨[enkon] enmity
悔恨[kaikon] regret
逆恨み[sakaurami] being resented in return
旧恨[kyuukon] old grudge

恨み[urami] resentment
恨みっこ無し[uramikkonashi] with no hard feelings
恨みっこのないように[uramikkononaiyouni] making it even
恨み言[uramigoto] grudge
恨む[uramu] to resent

吃逆[shakkuri] hiccough
悪逆[akugyaku] atrocity
悪逆無道[akugyakumudou] treacherous
可逆[kagyaku] reversible
可逆反応[kagyakuhannou] reversible reaction

逆さ[sakasa] reverse
逆に[gyakuni] conversely
逆らう[sakarau] to go against
逆ポーランド式[gyakupoorandoshiki] reverse Polish notation