Definitions of muscle:

• noun:   authority or power or force (especially when used in a coercive way)

  Example: "The senators used their muscle to get the party leader to resign"

• noun:   animal tissue consisting predominantly of contractile cells
• noun:   one of the contractile organs of the body
• noun:   muscular strength
• noun:   a bully employed as a thug or bodyguard

  Example: "The druglord had his muscleman to protect him"

• verb:   make one's way by force

  Example: "He muscled his way into the office"