Definition:
An ad hominem argument is any that attempts to counter another’s claims or conclusions by attacking the person, rather than addressing the argument itself.

Ad Hominem

-Fallacy Ex:
Premise: You loved The Matrix.
Premise: Keanu Reaves is in The Matrix
Premise: Keanu Reaves is in Speed.
Conclusion: You must love Speed.
(Affirming The Consequent Fallacy: you may have liked The Matrix even if you don't like Keanu Reaves, or in spite of the fact that he was in it, or maybe you liked him in it but hate him in everything else etc.)