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