-most
suffix/ˌməʊst/
Etymology From Middle English -most(e), from earlier -mest, from Old English -(e)mest, from Proto-Germanic *-umistaz, from the comparative suffix *-umô (from Proto-Indo-European *-mHo-) + the regular superlative suffix *-istaz (whence English -est). The Middle English form is due to conflation with the originally unrelated superlative most. See foremost for more.
1
Morpheme Furthest; -est; used to form superlatives of certain adjectives, especially directional and inherently-comparative ones.
- eastern + -most → easternmost
- nether + -most → nethermost