Full Idea
There are 'rebutting' defeaters against the truth of a previously justified belief, 'undercutting' defeaters against the power of the evidence, and 'reason-defeating' defeaters against the truth of the reason for the belief.
Gist of Idea
You can 'rebut' previous beliefs, 'undercut' the power of evidence, or 'reason-defeat' the truth
Source
Thomas Grundmann (Defeasibility Theory [2011], 'How')
Book Reference
'Routledge Companion to Epistemology', ed/tr. Bernecker,S/Pritchard,D [Routledge 2014], p.158
A Reaction
That is (I think) that you can defeat the background, the likelihood, or the truth. He cites Pollock 1986, and implies that these are standard distinctions about defeaters.