Šadvaitis

It could be a compound example: Šad-vaitis. The first syllable šad- is possibly personal (see Šãdžius), due to vai̇̃t- cf. lit. vȧ̃tas (DLKŽ). However, there may also be a derivative of the suffix -aitis from Šădžius: *Šadžiuvaitis, *Šadiuvaitis > Šadvaitis. For more on the creation, see Bliūdžiuvaitis.