washout

(wŏshˈoutˌ, wôshˈ-)

1. a. Erosion of a relatively soft surface, such as a roadbed, by a sudden gush of water, as from a downpour or floods.
   b. A channel produced by such erosion.
2. a. A total failure or disappointment.
   b. One who fails to measure up to a standard, especially one who fails a course of training or study.