The most random word that no one would ever look up on Urban Dictionary. It took me forever to find a word so random that only I would look it up.
However, if you must know, a footstep is:
1. The impression left in material steeped on by a foot or shoe.
2. An impact on something.
Man 1: "Dude, I can't believe I didn't get caught last night."
Man 2: "Did you cover your footprints? The cops can trace you by that now."
Man 3: "Oh shit."
Man 1: "I've been thinking, and I'm gonna try and reduce my carbon footprint from now on."
Man 2: "Fag."