c. 1300, "craving for food," from Anglo-French appetit, Old French apetit "appetite, desire, eagerness" (13c., Modern French appétit), from Latin appetitus "appetite, longing," literally "desire toward," from appetitus, past participle of appetere "to long for, desire; strive for, grasp at," from ad "to" (see ad-) + petere "go to, seek out," from PIE root *pet- "to rush, to fly."
Formerly with of or to, now with for. Of other desires or cravings, from late 14c. As an adjective, "characterized by appetite," OED and Century Dictionary list appetitious (1650s) and appetitual (1610s) as obsolete, but appetitive (1570s) continues.
suffix attached to verbs to mean their action, result, product, material, etc., from Old English -ing, also -ung, from Proto-Germanic *-unga-, *-inga- (cognates: Old Norse -ing, Dutch -ing, German -ung). In early use often denoting completed or habitual action; its use has been greatly expanded in Middle and Modern English.
"make hungry, give an appetite to," 1782 (implied in appetized), irregularly formed (on model of verbs in -ize) from appetite, or else a back-formation from appetizing. The French word is appétissant. "In Fr. only the pples. are found; and in English the simple vb. is perhaps only colloquial" [OED].
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Definitions of appetizing from WordNet
appealing to or stimulating the appetite especially in appearance or aroma;