Poisoning the Well

Poisoning the well is a preemptive attack on a person in order to discredit their testimony or argument in advance of their giving it. A person who thereby becomes unreceptive to the testimony reasons fallaciously and has become a victim of the poisoner. This is a kind of ad hominem.

Example:

[Prosecuting attorney in court] When is the defense attorney planning to call that twice-convicted child molester, David Barnington, to the stand? OK, I'll rephrase that. When is the defense attorney planning to call David Barnington to the stand?

Persuasive Definition

Some people try to win their arguments by getting you to accept their faulty definition. If you buy into their definition, they've practically persuaded you already. Same as the Definist Fallacy. Poisoning the Well when presenting a definition would be an example of a using persuasive definition.

Example:

Let's define a Democrat as a leftist who desires to overtax the corporations and abolish freedom in the economic sphere.