serio
serio is a Latin form of serius, meaning “serious; (serio) seriously”. It is the adverb.
Found 55 times in the Latin texts on Socratos.
Where it is used
Tacitus, Dialogus 1·26: … Graeculae alicui ancillae, cui adiungitur unus aut alter ex omnibus servis, plerumque vilissimus nec cuiquam serio ministerio adcommodatus. horum fabulis et erroribus et virides teneri statim et rudes animi imbuuntur; nec qu …
Plautus, Casina 4.2.790c: Serio.
Plautus, Epidicus 1.1.30a: Sérione dicis tu?
All forms of serius (declension table)
Source: Socratos (socratos.org), a free reader for Ancient Greek and Latin. Grammar from the Perseus Treebank and Morpheus; dictionary entries from Lewis & Short, A Latin Dictionary (Perseus Digital Library, CC BY-SA). Counts are from the texts on Socratos.