Sweat has a very distinguished ancestry. It comes from the Proto-Indo-European root sweid-, swoid-, swid-. The suffixed form swoidos (a noun) appears in Germanic as swaitaz, regularly becoming swāt in Old English, Schweiss in German, and sveiti in Old Norse. The related form swoidōs- regularly becomes the noun sūdōr- (inflectional stem of sūdor ) in Latin, from which English derives sudorific “causing sweat” and sudoriparous “secreting sweat.” Greek, as is common, goes its own way and forms its noun from the variant root swid- extended with the suffix -ro- ( swidro- ) to form hidrṓs, from which English derives hidrosis (excessive production of sweat); the Greek form is made obscure by the cluster sw- becoming h-. The form swidro- becomes sviêdri in Latvian, a Baltic language that, like Lithuanian, is very resistant to change.

Did you mean sweat out?