PIE *ghedhの「つなぐ、一致する」が語源で、語源的にはgatherと同じ。 godとは語源的に関係がない。
Why then, can one desire too much of a good thing. ["As You Like It"]As good as "practically, virtually" is from mid-14c.; to be good for "beneficial to" is from late 14c. To make good "repay (costs, expenses), atone for (a sin or an offense)" is from late 14c. To have a good mind "have an earnest desire" (to do something) is from c. 1500. Good deed, good works were in Old English as "an act of piety;" good deed specifically as "act of service to others" was reinforced early 20c. by Boy Scouting. Good turn is from c. 1400. Good sport, of persons, is from 1906. The good book "the Bible" attested from 1801, originally in missionary literature describing the language of conversion efforts in American Indian tribes. Good to go is attested from 1989.