posticous vs rearmost

posticous

adj
  • posterior 

  • Situated on the outer side of a filament; said of an extrorse anther. 

rearmost

adj
  • Furthest to the rear. 

  • The rearmost member of the strike team walked backward to guard them from a surprise attack from behind. 

How often have the words posticous and rearmost occurred in a corpus of books? (source: Google Ngram Viewer )