"significant, indicative, serving as a sign or warning" (as of danger), 1855, from Greek sēmat-, combining form of sēma (genitive sematos) "sign" (see semantic) + -ic. Used especially in biology, in reference to "warning" colors, etc. (by 1890).
"relating to significance or meaning," 1894, from French sémantique, applied by Michel Bréal (1883) to the psychology of language, from Greek sēmantikos "significant," from sēmainein "to show by sign, signify, point out, indicate by a sign," from sēma "sign, mark, token; omen, portent; constellation; grave" (Doric sama), from PIE root *dheie- "to see, look" (source also of Sanskrit dhyati "he meditates;" see zen).
The word has tended to become loose in application. Semanticize "invest (something) with meaning; analyze semantically" is by 1942.
Middle English -ik, -ick, word-forming element making adjectives, "having to do with, having the nature of, being, made of, caused by, similar to," from French -ique and directly from Latin -icus or from cognate Greek -ikos "in the manner of; pertaining to." From PIE adjective suffix *-(i)ko, which also yielded Slavic -isku, adjectival suffix indicating origin, the source of the -sky (Russian -skii) in many surnames. In chemistry, indicating a higher valence than names in -ous (first in benzoic, 1791).
In Middle English and after often spelled -ick, -ike, -ique. Variant forms in -ick (critick, ethick) were common in early Modern English and survived in English dictionaries into early 19c. This spelling was supported by Johnson but opposed by Webster, who prevailed.
<a href="https://www.etymonline.com/word/sematic">Etymology of sematic by etymonline</a>
Harper, D. (n.d.). Etymology of sematic. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/sematic