Etymology Dictionary

VAPID,  spiritless, flat, insipid.  (L.)   In Blount's Gloss., ed. 1674.   Prob. directly from Lat. uapidus, vapid, spoiled, flat, rather than from F. vapide, 'that sends up an ill fume,' marked by Cotgrave as a scarce or old word.—Lat. uappa, wine that has emitted its vapour, vapid or palled wine; closely allied to Lat. uap-or, vapour.   β. The Lat. uap-or stands for cuapor* (= cwapor), as is rendered almost certain by comparison with Gk. καπνός, smoke, καπύειν, to breathe forth; Lithuan. kwápas, breath, fragrance, evaporation, kwëpti, to breathe, smell, kwëpalas, perfume; Russ. kopote, fine soot, koptite, to smoke-dry; Curtius, i. 174.—✔KWAP, to reek, breathe out; Fick, i. 542.   Der. vapid-ly, -ness.   And see vapour, fade.