words wholly unrelated
crapper & crap
the former is coarse slang for the fixture into which one defecates. it got its name from thomas crapper, a plumber that installed and popularised—though did not invent—flushing toilets in the 1880s. crapper is an occupational surname derived from cropper which has been around since the 1200s.
the latter comes from the old french word crappe which means siftings or residue. its use as coarse slang for the act of defecation predates the birth of thomas crapper.
