swith
Quickly, speedily, promptly.
obsolete
As ye disown yon paughty dog, / That bears the keys of Peter, / Then swith! an' get a wife to hug,
Strongly; vehemently; very.
obsolete
Where it comes from
From Middle English swith, swithe, from Old English swīþe (“very much, exceedingly, severely, violently, fiercely”), from Proto-West Germanic *swinþā, from Proto-Germanic *swinþê (“strongly”), from Proto-Indo-European *swento- (“active, healthy”). Cognate with Saterland Frisian swied (“very”), West Frisian swiid (“very”), Dutch zwijd (“very, extremely”), Low German swied (“quite, very”), Dutch gezwind (“quick, swift”). Not related to superficially similar English swift.
Adapted from the Wiktionary entry swith (CC BY-SA 4.0).