Theorists have come up with many viable origins for the word "witch". The most popular of these are the Proto Indo-European Theories. They are weik1, weik2 and weid. Most English dictionaries will use one of these three sources to describe the origins of ‘witch’.
Weik is listed twice because, according to The American Heritage Dictionary of Indo-European Roots, weik actually has five distinct etymological branches but only two are attributed to the supernatural. In contrast, the Concise Dictionary of English Etymology, proponent of the ‘weid’ premise, states that ‘witch’ primarily comes from the word ‘witan’ through a series of phonetic changes. One well thought out argument for this theorem can be found at the following web site Draeconin by Tom Johnson.
Weik 1: in regards to sorcery and religious matters 
- OE: wigle (sorcery); wiglera, wiglere (sorcerer, seer or prophet); also > wil - MdE: wile; OF: and MF: guile
- wik- means holy
OHG: wïhen ; MdG: weihen (to consecrate): MHG: wïch (holy)
ON: vigja (also to consecrate),
L: victima (sacrifice)
- [wikke pertains to magic and sorcery only.]
MG: wikken (to predict) OHG: wicken (to work magic) wikkerie(witchery)
LS: wiken, wicken. wigelen and wichelen (conjuring; soothsaying) ; wikker, wichler (fortune-telling) ; wikkerske (witch) ; wichelie (sorcery)
OE: wicca(m.), wicce (f.)(witch); wiccian (to work sorcery, bewitch) wicce-craeft (witchcraft) ME: witche and MdE: witch
Weik 2: bend or fold
- OE: wican (to bend) from which MdE weak, wicker and witch elm
OS: wican - wikan,
OHG: wichan, wicken (to bend)
ON: vikja (bend) vika (to fold)
Weid: to see or to know. Semantically, seeing and knowing are connected in Indo-European languages.
- weid or wid
- L: video videre (to see); saga (female witch) > MdE Sage Sagacious
G: wissen (to know); witken (to exercise ones knowledge)
E: wit (knowledge); witan (to know) witega (seer magician, prophet, sorcerer)
ON:, vitugr, vitka, vekka (vekke) (wise one)
There are other etymology theories but they are not widely accepted. There is ‘wat’ meaning prophecy, inspiration and ecstasy. Then there is ‘weg’ (OE: weccan) from which we get ‘watch’ and ‘wake’ and perhaps even German’s ‘wikkjaz’ –literally meaning ‘one who wakes the dead’.
 In Nigel Jackson’s book Call of the Horned Piper they are listed as weik, wid and wat.
 The branch that refers to bend or fold has been connected to magic by some; as in the manipulation of energy. This is a very abstract and convoluted association. I disagree with this assesement but included it for the scope of the article.
 A History of Witchcraft, Russell B Jeffery; pg. 177
 Presently, I cannot find much information on this particular theory,
 Online Etymology