英语词源字典 - 在线词源网站

forgiving (adj.)[forgiving 词源字典]: "inclined to forgive," 1680s, from present participle of forgive. Related: Forgivingness. [forgiving etymology, forgiving origin, 英语词源]
misgiving (n.): c. 1600, "feeling of mistrust or sudden apprehension," verbal noun from misgive "cause to feel doubt" (1510s), usually said of one's heart or mind, from mis- (1) + give (v.) in its secondary Middle English sense of "suggest." Related: Misgivings.
thanksgiving (n.): 1530s, "the giving of thanks," from thanks (n.) + present participle of give (v.). In the specific sense of "public celebration acknowledging divine favors" thanksgiving dates from 1630s (the first one in America was held October 1621 by Plymouth Colony Pilgrims in appreciation of assistance from members of the Massasoit tribe and celebration of the first harvest); though Thanksgiving Day itself is not attested until 1670s.
unforgiving (adj.): 1713, from un- (1) "not" + present participle adjective from forgive. Old English had unforgifende.