Nager entre deux eaux = (lit.) To swim under water; (fig.) To run with the hare and hunt with the hounds.

Faire eau (of boats) = To spring a leak.

Faire de l’eau (of boats) = To take in fresh water.

Laissez couler l’eau = Do not be anxious about what cannot be helped; Don’t cry over spilt milk.

Cela s’en est allé en eau de boudin = That collapsed utterly, came to nothing.

[The more correct form is s’en aller en aune de boudin, alluding to Perrault’s tale of Les Souhaits Ridicules.]

Échapper

Ce mot m’est échappé = That word escaped me inadvertently (i.e., I did not mean to say it).

Ce mot m’a échappé = I have forgotten that word.