Sweat, Sweet Surname and related Variants

Sweat
Probably a variant of English Sweet.

Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4

Sweet
English (most common in the West Country): nickname from Middle English swete ‘sweet’, ‘pleasant’, ‘agreeable’. The Old English bynames Swet(a) (masculine) and Swete (feminine) derived from this word survived into the early Middle English period, and may also be sources of the surname.
Translation of German and Jewish (Ashkenazic) Suess.
In New England, a translation of French Ledoux.

Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4

Suess
German (Süss) and Jewish (Ashkenazic): nickname or Jewish ornamental name from Middle High German, German süss ‘sweet’, ‘pleasant’, ‘agreeable’.

Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4

Ledoux
French: nickname from le doux ‘the sweet (one)’ (from Old French dolz, dous). This name is often translated as Sweet, and translations to Fresh are also attested. See also Ladue.

Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4

Ladue
Americanized form of French Ledoux, with the use of the feminine article in place of the masculine that is characteristic of family names in Canada and New England.

Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4