The first meaning of this word that comes to mind for me is 'to rip off'. Like demanding a much higher price for something than seems fair. Someone who does that can be referred to as 'een afzetter'. his is a common use of this word. It can also mean 'to push off of something'. Like a swimmer does against the side of a pool to move himself forward faster, 'de zwemmer zet zich af'. This is also a common use.

To drop off. - Ik heb hem hier afgezet. --> I dropped him off here. I brought him here. To block - De straat is door de politie afgezet --> The street is blocked by the police (with e.g. ribbons) Do NOT use "afgezet" if a vehicle is blocking the road/street so you cannot pass it.

The meanings mentioned by Emile are the most common, I think. Two other meanings: 1. "De dictator werd afgezet." That translates to something like "The dictator was ousted from power." 2. "Ik heb het programma afgezet, want ik vond het verschrikkelijk." "I switched off the program, because I found it terrible." I'm not sure how to translate it better. With this wording, it's left unclear wether the person has switched off the tv or radio, or he/she simply has chosen another channel.

De TROS heeft de quizshow XY afgezet. Dat betekent dat de quizshow XY niet meer op TV wordt uitgezonden. De volksuniversiteit in Düsseldorf heeft de conversatiecursus Nederlands afgezet. Dat betekent dat deze conversatiecursus niet meer wordt aangeboden.