back seat vs rearward

back seat

noun
  • Any of the seats in the rear of a vehicle. 

  • A lesser or inferior position; a position of deliberate noninvolvement, in which decision-making or leadership is left to others. 

rearward

noun
  • The part that comes last or is situated in the rear; conclusion, wind-up. 

  • The last troop; the rear of an army; a rear guard. 

adj
  • Toward the back or rear of something. 

adv
  • Toward the back or rear of something. 

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