Expressing regret is an important part of communication, as it allows us to acknowledge our mistakes and show remorse. The crossword solutions for the term EXPRESS REGRET are APOLOGISE (9 letters), RUE (3 letters), MOAN (4 letters), and BEMOAN (6 letters). Apologising is a formal way of expressing regret, while rueing is a more informal way of expressing sorrow or regret. Moaning and bemoaning are both ways of expressing sorrow or regret through vocalisation.