"You canker blossom!" 3 Shakespearean Insults
Old English soð "truth, justice, righteousness, rectitude; reality, certainty," noun use of soð (adj.) "true, genuine, real; just, righteous," originally *sonð-, from Proto-Germanic *santhaz (cf. Old Norse sannr, Old Saxon soth, Old High German sand "true," Gothic sunja "truth").
The group is related to Old English synn "sin" and Latin sontis "guilty" (truth is related to guilt via "being the one;" see sin (v.)), from PIE *es-ont- "being, existence," thus "real, true," from present participle of root *es-, the s-form of the verb "to be" (see be), preserved in Latin sunt "they are" and German sind. Archaic in English, it is the root of modern words for "true" in Swedish (sann) and Danish (sand). In common use until mid-17c., then obsolete until revived as an archaism early 19c. by Scott, etc. Used for Latin pro- in translating compounds into Old English, e.g. soðtacen "prodigy," soðfylgan "prosequi."
Old English soðian "show to be true," from soð "true" (see sooth). Sense of "quiet, comfort, mollify" is first recorded 1690s, via notion of "to assuage one by asserting that what he says is true" (i.e. to be a yes-man), a sense attested from 1560s (and cf. Old English gesoð "a parasite, flatterer"). Meaning "reduce the intensity" (of a pain, etc.) is from 1711. Related: Soothed; soothing.