Reconstruction:Proto-Celtic/-yūs

Etymology
From.

Suffix

 * (whence 🇨🇬 and 🇨🇬)
 * (whence 🇨🇬 and 🇨🇬)

Usage notes

 * No gender/number/case inflection of comparative adjectives is attested in Celtic. This suffix lost all productivity in Brythonic but a few remnants remain (such as 🇨🇬 < ).
 * Some adjectives that used a suffix in the positive that was absent in the other degrees of comparison did not use . Instead they used  to form the comparative.