1. a blemish made by dirt;

"he had a smudge on his cheek"

2. an act that brings discredit to the person who does it;

"he made a huge blot on his copybook"

1. smear so as to make dirty or stained

2. charge falsely or with malicious intent; attack the good name and reputation of someone;

"The journalists have defamed me!" "The article in the paper sullied my reputation"