riant
adjective
ri·ant ˈrī-ənt 
ˈrē-;
rē-ˈäⁿ
literary
: cheerful, mirthful
… the character of the grounds in which the Abbey stood; which were riant and secluded, umbrageous, and full of the sound of falling waters.
John Stuart Mill
John Stuart Mill riantly
ˈrī-ənt-lē
adverb ˈrē-
Word History
Etymology
Middle French, present participle of rire to laugh, from Latin ridēre
First Known Use
1567, in the meaning defined above