outermost

The story

1. Old English · inherited fromūtemest
2. Middle English · inherited fromuttermost
3. English todayoutermost

From Middle English uttermost, uttirmest, uttermast, outemast, alteration (due to Middle English outre (“outer”)) of Old English ūtemest, ȳtemest (“outermost”), equivalent to outer + -most. Doublet of uttermost.