Here is the complete expansion of the Indo-European root of the word "witch",
from THE AMERICAN HERITAGE DICTIONARY OF INDO-EUROPEAN ROOTS, revised & edited
by Calvert Watkins (Houghton Mifflin Co.: Boston, 1985; ISBN 0-395-36070-6):

WEIK- [1].  Clan (social unit above the household).  1. Suffixed form *WEIK-
SLA in Latin VILLA, country house, farm: VILLA, VILLAGE, VILLAIN, VILLANELLE,
(VILLEIN); (BIDONVILLE).  2. Suffixed o-grade form *WOIK-O in: a. Latin VICUS,
quarter or district of a town, neighborhood: (VICINAGE), VICINITY; b. Greek
OIKOS, house, and its derivativ e OIKIA, dwelling: ANDROECIUM, AUTOECIOUS,
DIOCESE, DIOECIOUS, DIOICOUS, ECESIS, ECOLOGY, ECONOMY, ECUMENICAL,
HETEROECIOUS, MONOECIOUS, PARISH, TRIOUECIOUS.  3. Zero-grade from *WIK- in
Sanskrit VIS- dwelling, house, with derivative VAISYAH, settler: VAISYA.

WEIK- [2].  In words connectid with magic and religious notions (in Germanic
and Latin).  1. Germanic suffixed form *WIH-L- in Old English WIGLE,
divination, sorcery, akin to the Germanic source of Old French GUILE, cunning
trickery: GUILE.  2. Germanic expressive form *WIKK- in: a. Old English WICCA,
wizard, and WICCE, witch: WITCH; b. Old English WICCIAN, to cast a spell:
BEWITCH.  3. Possible suffixed zero-grade form *WIK-T-IMA in latin VICTIMA,
animal used as sacrifice, victim (although this may belong to another root
*[SHWA]WEK- not otherwise represented in English): VICTIM.

WEIK- [3].  To be like.  1. Suffixed variant form *EIK-ON- in Greek EIKON,
likeness, image: ICON, (ICONIC), ICONO-; ANISEIKONIA.  2. Prefixed and
suffixed zero-grade form *N-WIK-ES, not like (*N-, not), in greek AIKES,
unseemly: AECIUM.

WEIK- [4]. Also WEIG-.  To bend, wind.  I. Form WEIG-. 1. Germanic *WIK- in:
a. Old English WICE, wych elm (having pliant branches): WYCH ELM; b. Swedish
VIKER, willow twig, wand, akin to the Scandinavian source of Middle English
WIKER, wicker: WICKER; c. Old Norse vikja, to bend, turn, probably akin to the
Scandinavian source of Old Nort h French WIKET, wicket (< "door that turns?):
WICKET.  2. Germanic *WAIKWAZ in: a. Old Norse VEIKR, pliant: WEAK; b. Dutch
WEEK, weak, soft: WEAKFISH.  3. Germanic *WIKON-, "a turning," series, in Old
English WICU, WICE, week: WEEK.  II. Form *WEIK-.  Zero-grade form *WIK- in:
a. Latin VIX (genetive VICUS), turn, situation, change: VICAR (VICARIOUS),
VICE[3]; VICISSITUDE; b. Latin VICIA, vetch (< "twining plant"): VETCH.

WEIK- [5].  To fight, conquer.  1. Germanic *WIK- in Old Norse VIGR, able in
battle: WIGHT[2].  2. Nasalized zero-grade form *WI-N-K- in Latrin VINCERE
(past participle VICTUS), to conquer: VANQUISH, VICTOR, VINCIBLE; CONVINCE,
EVICT.