"near, nearby, close together, adjacent," Middle English neigh, from Old English neah (West Saxon, Kentish), neh (Anglian), from Proto-Germanic *naehwa- (source also of Old Saxon nah, Old Frisian nei, Middle Dutch, Dutch na, Old High German nah, German nah, Gothic nehwa), of uncertain origin, with no cognates outside Germanic. The Old English progression was neah - near - niehsta, for "nigh - nigher - nighest." But the comparative near and the superlative nehst (see next) gradually evolved into separate words that were no longer felt as related to nigh. New comparative and superlative forms nigher, nighest developed 14c. as phonetic changes obscured the original relationships. As an adjective and preposition in Middle English.
"to spring, rise, gush," Old English wiellan (Anglian wællan), causative of weallan "to boil, bubble up, rise (in reference to a river)" (class VII strong verb; past tense weoll, past participle weallen), from Proto-Germanic *wellanan "to roll" (source also of Old Saxon wallan, Old Norse vella, Old Frisian walla, Old High German wallan, German wallen, Gothic wulan "to bubble, boil"), from PIE root *wel- (3) "to turn, revolve," on notion of "roiling or bubbling water."
"in a satisfactory manner," Old English wel "abundantly, very, very much; indeed, to be sure; with good reason; nearly, for the most part," from Proto-Germanic *wel- (source also of Old Saxon wela, Old Norse vel, Old Frisian wel, Dutch wel, Old High German wela, German wohl, Gothic waila "well"), from PIE root *wel- (2) "to wish, will" (source also of Sanskrit prati varam "at will," Old Church Slavonic vole "well," Welsh gwell "better," Latin velle "to wish, will," Old English willan "to wish;" see will (v.)).
Also used in Old English as an interjection and an expression of surprise. The adjective was in Old English in the sense "in good fortune, happy," from the adverb; sense of "satisfactory" is from late 14c.; "agreeable to wish or desire" is from mid-15c.; "in good health, not ailing" is from 1550s. Well-to-do "prosperous" is recorded by 1794.