Ragged, worn-out; also, hackneyed, tired.
Of a page in a book or other publication: having its corner folded down, either due to having been read many times, or intentionally as a sort of bookmark.
Untidy in appearance.
Scurfy.
An artificial intelligence researcher who believes that intelligence is too complicated (or computationally intractable) to be solved with the sorts of homogeneous system favoured by the "neats".