Most distant or remote; farthest in distance or position.
From 'far' + '-most' superlative suffix (from Old English 'mǽst'). This is an archaic or poetic superlative form; modern English typically uses 'farthest' instead, making 'farmost' largely obsolete.
English superlatives are fascinating because some are synthetic (-est) and others are irregular ('farthest' instead of 'farmost'). The fact that 'farthest' won out over 'farmost' shows how language naturally simplifies and regularizes itself over time.
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