gusto

First recorded in 1620–30; from Italian, from Latin gustus; see gust²

Gusto comes from the Italian noun gusto “taste, flavor,” from Latin gustus “tasting, flavor, sense of taste,” which is also the source of French goût “taste, flavor, relish.” Gustus is a derivation from the verb gustāre “to taste, taste the flavor of.” Gustāre comes from the Proto-Indo-European root geus-, gus- “to taste, choose.” The root appears in Greek geúesthai “to taste” and geúein “to give a taste” (from unrecorded geúsesthai and geúsein: Greek loses the original s between vowels). Geus- and gus- become keus- and kus- in Germanic, forming the verb keusan “to choose,” which becomes kiusan in Gothic, cēosan in Old English, and choose in English.
In the days of the Holy Roman Empire, a Kurfürst “Prince-Elector” ( Princeps Elector in Latin) was one of the German princes who were members of the electoral college that elected the Kaiser “Emperor.” Kur-, the first element of Kurfürst, comes from Germanic kus-: the s becomes r by rhotacism (this same change process is seen in the English pair was, were and the Latin change of lases to lares ).
The same Germanic root appears in the second element of Valkyrie “(in Norse mythology) one of the maidens who served Odin,” which comes from the Old Icelandic noun valkyrja “(female) chooser of the slain.”
The main current sense of gusto, “keen enjoyment,” first appeared in 1629 but only started to become very common in the early 19th century.