gus ‧ to /ˈɡʌstəʊ $ -toʊ/ BrE AmE noun [uncountable]
[ Date: 1600-1700 ; Language: Italian ; Origin: Latin gustus 'taste, liking' , from gustare ; GUSTATORY ]
with gusto if you do something with gusto, you do it with a lot of eagerness and energy:
They sang hymns with great gusto.