Could the word <<Objective>> be used instead of aim? Or would it be another word in Greek?
The word σκοπός is actually never used for people. It might translate to aim, but with the meaning of purpose rather than target.
If someone wanted to refer to an actual person, they would probably use στόχος, and translate the sentence to "He is not my target".
I hope it's clear enough ^.^ (That is, if I understood your question correctly. :P)