something that has happened and cannot be changed I should probably have asked for more money when I was offered the job, but hey, that's water under the bridge now. A past occurrence, especially something unfortunate, that cannot be undone or rectified: All that is now just water under the bridge. e.g. Simeone has a no nonsense style and would take no prisoners at Old Trafford - and surely enough water has passed under the bridge since his antics got former Red Devils man David Beckham sent off at the 1998 World Cup.