vatic (adj.)

1620s, "poet or bard," specifically "Celtic divinely inspired poet" (1728), from Latin vates "sooth-sayer, prophet, seer," from a Celtic source akin to Old Irish faith "poet," Welsh gwawd "poem," from PIE root *wet- (1) "to blow; inspire, spiritually arouse" (source also of Old English wod "mad, frenzied," god-name Woden; see wood (adj.)). Hence vaticination "oracular prediction" (c. 1600).

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.