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finicky (adj.)[finicky 词源字典]: 1825, "dainty, mincing," from finical "too particular" (1590s), which perhaps is from fine (adj.) + -ical as in cynical, ironical (OED says "ultimate derivation" from the adjective "seems probable"). But finikin (1660s) "dainty, precise in trifles" has been proposed as a source, even though the timing is off. It apparently comes from Dutch; compare Middle Dutch fijnkens (adv.) "precisely, exactly," from fijn, cognate with English fine (adj.).

The -k- between the final -c- and a suffix beginning in -i, -y, or -e is an orthographic rule to mark the pronunciation of -c- as "k" (compare picnicking, trafficking, panicky, shellacked). Related: Finickiness.[finicky etymology, finicky origin, 英语词源]
nicky-tam (n.): also nicky tam, "garter worn over trousers," 1911, from Scottish, from shortened form of knickers + Scottish & northern English dialect taum, from Old Norse taumr "cord, rein, line," cognate with Old English team (see team). Originally a string tied by Scottish farmers around rolled-up trousers to keep the legs of them out of the dirt.
panicky (adj.): 1869, from panic (n.1) + -y (2). Related: Panickiness.