What's the adjective for backwash? Here's the word you're looking for.
Included below are past participle and present participle forms for the
verbs backwind and backwash which may be used as adjectives within certain contexts.
backward
(of motion) Pertaining to the direction towards the back.
(of motion) Pertaining to the direction reverse of normal.
“With a backward lunge, he threw himself clear of the closet, perhaps trying to shield her.”
“He has never flinched, never buckled, never taken a backward step in defending the rights of our editors and journalists to find the news and report it in a fair and balanced way.”
“It cannot be considered a backward culture, but rather has to be seen as a different culture.”