出典:Wiktionary
From Middle English siker, sikker, sykkere, secre, seccre, from 古期英語 sēocra (“sicker”), equivalent to sick + -er.
From Middle English siker, from 古期英語 sicer, sicor, from Proto-West Germanic *sikur (“free, secure”), from Latin sēcūrus (“secure”, literally “without care”). Doublet of sure and secure.
From Middle English *sikeren (attested only as sikeriez (“(it) trickles, (it) leaks, (it) oozes”)), from 古期英語 sicerian (“to ooze, seep”), from Proto-West Germanic *sikarōn, from Proto-Germanic *sikarōną (“to trickle”), from Proto-Germanic *sīką (“slow running water”). Cognate with German Low German sickern (“to seep”), German sickern (“to seep, trickle”). Akin also to English sitch.
sicker (三人称単数 現在形 sickers, 現在分詞 sickering, 過去形および過去分詞形 sickered)
Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
(See the entry for sicker in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913)