before vowels Sin-, word-forming element meaning "Chinese," 1879, from Late Latin Sinæ (plural) "the Chinese," from Ptolemaic Greek Sinai, from Arabic Sin "China," which is probably from Chinese Ch'in (modern transliteration Qin), name of the fourth dynasty of China (see China). The alternative Sinico- is from the combining form Medieval Latin Sinicus.
word-forming element making nouns implying a practice, system, doctrine, etc., from French -isme or directly from Latin -isma, -ismus (source also of Italian, Spanish -ismo, Dutch, German -ismus), from Greek -ismos, noun ending signifying the practice or teaching of a thing, from the stem of verbs in -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached. For distinction of use, see -ity. The related Greek suffix -isma(t)- affects some forms.
<a href="https://www.etymonline.com/word/Sinicism">Etymology of Sinicism by etymonline</a>
Harper, D. (n.d.). Etymology of Sinicism. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/Sinicism