A word to stand on its own would be a word that is a sentence on its own.
Words Like This Are: And, Eat, Play most adjectives. Because if your friend asked you what you wanted to do you would simply say "Play." or "Read." or such thing as your name can be a word to stand on its own. If you meet a new person and they introduce themselves and ask for your name, typically you are to say "Bob." or "John." or whatever you name might be.
Hope it helped.
Sincerely,
xPain