noun
night soil collector
Historical occupation; colloquial term for someone who collected human waste for use as fertilizer. Now obsolete in practice.
江戸時代には、おわい屋が町のし尿を集めて農家に売っていた。
In the Edo period, night soil collectors gathered human waste from towns and sold it to farmers.
Compound of おわい (night soil, from 汚穢) and 屋 (shop, dealer). The exact derivation of おわい is uncertain.