ad hominem (abusive):
instead of attacking an assertion, the argument attacks the person who made the assertion. (such as calling someone a liar.).
EXAMPLE: You may argue that Kerry is a war hero, but you are just a liberal & a liar. (ad hominem abusive)
ad hominem (circumstantial):
instead of attacking an assertion, the author points to the relationship between the person making the assertion
and the person's circumstances.
EXAMPLE: We should discount what Premier Klein says about taxation because he is too rich to care about the increase. (ad hominem
circumstantial)
ad hominem (tu quoque):
this form of attack on the person notes that a person does not practice what he preaches
EXAMPLE: You say I shouldn't drink, but you haven't been sober for more than a year. (ad hominem tu quoque) - (pronounced "too quo kwee")