noun
1. the retreating or flowing back of a tidal flow from the land to the sea; ebb tide.
2. the act or condition of decline or regression, as from a high state to a low one.
the slow ebb of her strength
fortunes at a low ebb
intransitive verb
1. of a tide, to flow away from land; recede.
2. to weaken, decline, or decay.
As knowledge grows, religious faith sometimes ebbs.