Words related to will

shall (v.)

Old English sceal, Northumbrian scule "I owe/he owes, will have to, ought to, must" (infinitive sculan, past tense sceolde), from *skulanan, a common Germanic preterite-present verb (along with can, may, will), from Proto-Germanic *skul- (source also of Old Saxon sculan, Old Frisian skil, Old Norse and Swedish skola, Middle Dutch sullen, Old High German solan, German sollen, Gothic skulan "to owe, be under obligation"). This is said to be related, via a past tense form, to Old English scyld "guilt," German Schuld "guilt, debt;" also Old Norse Skuld, name of one of the Norns.

These Germanic words are reconstructed (Watkins, Pokorny) to be from a PIE root *skel-(2) "to be under an obligation." The basic sense of the Germanic word probably was "I owe," hence "I ought." Cognates outside Germanic include Lithuanian skelėti "to be guilty," skilti "to get into debt;" Old Prussian skallisnan "duty," skellants "guilty." But Boutkan gives the group no PIE etymology and writes that the alleged root, limited as it is to Germanic and Balto-Slavic, "is likely to represent an innovation on the basis of North European substrate material."

Shall survives as an auxiliary. The original senses are obsolete; the meaning shifted in Middle English from obligation to include futurity. It has no participles, no imperative, and no infinitive. Its past-tense form has become should (q.v.) and has acquired special senses of its own.

good will (n.)
Old English godes willan "state of wishing well to another;" see good (adj.) + will (n.). Meaning "cheerful acquiescence" is from c. 1300. In the commercial sense "degree of favor enjoyed through patronage of customers" from 1570s.
self-willed (adj.)

"obstinate, unmindful of the will or wishes of others," late 15c., from self-wille "obstinate or perverse insistence on one's own desires or opinions" (mid-14c.); see self + will (n.). Old English selfwill, selfwyll meant "free will."

Self-willedness "quality or condition of being self-willed" is from mid-15c., though it is not certain whether "obstinacy" or "self-reliance" is implied.

Middle English also had an adjective self-willy (15c.), and the adverb self-willes is attested from late 12c. as "willingly, voluntarily;" late 14c. as "willfully, stubbornly."

welcome (n.)
Old English wilcuma "welcome!" exclamation of kindly greeting, from earlier wilcuma (n.) "welcome guest," literally "one whose coming suits another's will or wish," from willa "pleasure, desire, choice" (see will (n.)) + cuma "guest," related to cuman "to come," from PIE root *gwa- "to go, come." Similar formation in Old High German willicomo, Middle Dutch wellecome.

Meaning "entertainment or public reception as a greeting" is recorded from 1530. The adjective is from Old English wilcuma. You're welcome as a formulaic response to thank you is attested from 1907. Welcome mat is from 1908; welcome wagon is attested from 1940.
willful (adj.)
also wilful, c. 1200, "strong-willed," usually in a bad sense, "obstinate, unreasonable," from will (n.) + -ful. From late 14c. as "eager" (to do something). Mid-14c., of actions, "done on purpose, intentional, due to one's own will." Related: Willfullness.

masc. proper name, from Old North French Willaume, Norman form of French Guillaume, of Germanic origin (cognates: Old High German Willahelm, German Wilhelm), from willio "will" (see will (n.)) + helma "helmet," from Proto-Germanic *helmaz "protective covering" (from PIE root *kel- (1) "to cover, conceal, save;" compare helm (n.2)). After the Conquest, the most popular given name in England until supplanted by John.

willpower (n.)
also will power, 1847, from will (n.) + power (n.).
benevolence (n.)

c. 1400, "disposition to do good," from Old French benivolence (Modern French bienveillance) and directly from Latin benevolentia "good feeling, good will, kindness," from bene "well" (see bene-) + volentem (nominative volens) present participle of velle "to wish" (see will (v.)). In English history, this was the name given to forced extra-legal loans or contributions to the crown, first so called 1473 by Edward IV, who cynically "asked" it as a token of good will toward his rule.

benevolent (adj.)

mid-15c., "wishing to do good, well-disposed, kindly," from Old French benivolent and directly from Latin benevolentem (nominative benevolens) "wishing (someone) well, benevolent," related to benevolentia "good feeling," from bene "well" (see bene-) + volentem (nominative volens) present participle of velle "to wish" (see will (v.)). Related: Benevolently.

Deo volente 

1767, Latin, "God willing," that is, "if nothing prevents it, if it is meant to be," a sort of verbal knock on wood, from ablative of Deus "God" (see Zeus) + ablative of volentem, present participle of velle "to wish, will" (see will (v.)). Often abbreviated D.V.