soil (v.)

early 13c., "to defile or pollute with sin," from Old French soillier "to splatter with mud, to foul or make dirty," originally "to wallow" (12c., Modern French souillier), from souil "tub, wild boar's wallow, pigsty," which is from Latin solium "tub for bathing; seat" (from PIE root *sed- (1) "to sit") or else from Latin suculus "little pig," from sus "pig." The literal meaning "to make dirty on the surface, begrime" is attested from c. 1300 in English. Related: Soiled; soiling.

c. 1300, "land, area, place," from Anglo-French soil "piece of ground, place" (13c.). It is attested from late 14c. as "the earth, the ground," and mid-15c. as "mould, earth, dirt," especially that in which plants grow. The meaning "one's land, place of one's nativity" is from c. 1400.

The word seems to be a merger or confusion of three words in Old French: 1. sol "bottom, ground, soil" (12c., from Latin solum "soil, ground;" see sole (n.1)); 2. soeul, sueil "threshold, area, place" (from Latin solium "seat," from PIE root *sed- (1) "to sit"); 3. soil, soille "a miry place," from soillier "splatter with mud" (see soil (v.)).

"filth, dirt, refuse matter, sewage, liquid likely to contain excrement," c. 1600, a sense extended from Middle English soile "miry or muddy place, bog," especially as a wallow for a hog or a refuge for a hunted deer (early 15c.), from Old French soille "miry place," from soillier (v.) "to make dirty," and in part a native formation from soil (v.). In form and senses also much influenced by soil (n.1). This is the word in the plumber's soil pipe (by 1833) and archaic night-soil.