Adjective: The green color around the white parts of your shoes, like the toes of Chuck Taylors, the first time you use them to mow the lawn.
Noun: A tennis shoe with green on them after you mow the lawn for the first time in those shoes.
Beau: "Oh man! I forgot I was wearing my new shoes when I mowed the lawn! Now they're all green!"
Mick: "Dude. You have a bad case of mowtoe."
Paul: "Dude, what's with the green on your Chuckie T's?"
Tim: "I couldn't find my work boots, so I had to wear these shoes to mow the lawn. I hate mowtoe."