an attack against the person WITHOUT ADDRESSING THE LOGIC OR THE ISSUES
an attack on the argument based on irrelevant claims relating to the speaker
an obvious signaling device of a weak argument as the individual offering it realizes that the dispute can not be countered with reason or evidence to the contrary, thus necessitating a deflection from the heart of the matter
an unwarranted attack on the person to discredit their arguments
a personal attack that has no bearing on the issue at hand