serio
From LSJ
εἰ δὲ τύχῃ τις ἔρδων, μελίφρον' αἰτίαν ῥοαῖσι Μοισᾶν ἐνέβαλε → if someone is successful in his deeds, he casts a cause for sweet thoughts into the streams of the Muses
Latin > English
serio ADV :: seriously, in earnest
Latin > English (Lewis & Short)
sērĭō: adv., v. serius.
Latin > French (Gaffiot 2016)
sērĭō,¹¹ sérieusement : Pl. Amph. 906 ; Ter. Haut. 541 ; Liv. 7, 41, 3 ; Plin. Min. Ep. 2, 20, 10.
Latin > German (Georges)
sēriō, Adv., s. 1. sērius, a, um.