The Collaborative International Dictionary of English v.0.48:

Shoulder \Shoul"der\, v. t. [imp. & p. p. Shouldered; p. pr. &
   vb. n. Shouldering.]
   1. To push or thrust with the shoulder; to push with
      violence; to jostle.
      [1913 Webster]

            As they the earth would shoulder from her seat.
                                                  --Spenser.
      [1913 Webster]

            Around her numberless the rabble flowed,
            Shouldering each other, crowding for a view. --Rowe.
      [1913 Webster]

   2. To take upon the shoulder or shoulders; as, to shoulder a
      basket; hence, to assume the burden or responsibility of;
      as, to shoulder blame; to shoulder a debt.
      [1913 Webster]

            As if Hercules
            Or burly Atlas shouldered up their state. --Marston.
      [1913 Webster]

   Right shoulder arms (Mil.), a position in the Manual of
      Arms which the piece is placed on the right shoulder, with
      the lock plate up, and the muzzle elevated and inclined to
      the left, and held as in the illustration.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shouldered \Shoul"dered\, a.
   Having shoulders; -- used in composition; as, a
   broad-shouldered man. "He was short-shouldered." --Chaucer.
   [1913 Webster]

WordNet (r) 3.0 (2006):

shouldered
    adj 1: having shoulders or shoulders as specified; usually used
           as a combining form; "stoop-shouldered"; "broad-
           shouldered"