A word having the same sound, or even the same spelling, as another but having different meaning or origin.
I made them up because the definition of a homonym is a useful way in to discuss character. There is a character type who, upon being asked to attempt something new, untried, potentially risky, will say yes. Then there is the type who, being asked the same question, will say no.
The character who says, 'yes' can be described as foolhardy, inconsiderate of risk, excitable by nature. This character is unreliable. This character takes on too much responsibility. This character might fail.
The character who says, 'no' is sensible, cautious, does not over-extend his/her energies. Is calm. In refusing risk, this character makes fewer mistakes. This character can be depended upon. To say no is a good trait. After all, where would we be if everyone said 'yes' to new things? Who would be blameless then?
To examine the origins of 'yes' and 'no' characters would be an interesting exercise. To ask which type is likely to be happier would be another interesting exercise. So there it is, a writing exercise just made: define a challenge for a character-type to encounter and overcome. Choose either a 'yes' or 'no' type...