Proto-IE: *m[e]ud-
Meaning: to be glad
Old Indian: módate 'to be merry, glad, rejoice', ptc. mudita-; móda- m., mud-, mudā f. 'pleasure, joy', mudrá- 'joyous, glad'
Avestan: moaδanōkarana- 'Wollust bereitend'
Russ. meaning: радоваться
References: Fraenkel 467