The Collaborative International Dictionary of English v.0.48:
Ebb \Ebb\, v. i. [imp. & p. p. Ebbed; p. pr. & vb. n.
Ebbing.] [AS. ebbian; akin to D. & G. ebben, Dan. ebbe. See
1. To flow back; to return, as the water of a tide toward the
ocean; -- opposed to flow.
That Power who bids the ocean ebb and flow. --Pope.
2. To return or fall back from a better to a worse state; to
decline; to decay; to recede.
The hours of life ebb fast. --Blackmore.
Syn: To recede; retire; withdraw; decay; decrease; wane;