The etymology of this word comes from an invisible proto-language. If you're confident you know the etymology, feel free to add it, but reader beware should the etymology be added by someone other than the creator of the language!
Suffix
-ī
Used to form adverbs from the base (positive) form of class II and class IIIadjectives, equivalent to English -ly, and to form the adverbial suffixes for superlative adverbs of all three declensions.