Reconstruction:Proto-Celtic/-om

Suffix

 * (cf. )
 * (cf., a zero-grade formation)
 * (cf., a zero-grade formation)

Usage notes

 * Only prefixed verbs can use this suffix to make their verbal nouns. Simple, unprefixed verbs must use a different suffix or formation, even if it has related prefixed verbal nouns in -om.
 * Due to extensive final syllable apocope, the suffix phonetically vanished in all Insular Celtic descendants. By Old Irish, the only traces of the suffix are its mutational effects and the resulting verbal nouns' apparent lack of a derivational suffix. The loss of the neuter further incinerated these last traces of the suffix.