muffled-not loud because of being obstructed in some way.
Alley-a small road that ends up behind a building.
Tramp-the sound soldiers make when marching.
Stealthy-to do something in a cautious manner so you are not seen or heard.
Sombre-oppressively solemn or sober in mood; grave.
Impetuous-acting or done quickly and without thought or care.
Defiance-to do something that is a challenge.