The period near the end of a prolonged bear market. In a graveyard market, long-time investors have taken large losses, while new investors prefer to stay liquid by sitting on the sidelines and keeping their money in cash or cash-equivalent securities until market conditions improve.
The term graveyard market is an apt description of this market phenomenon: the investors in a graveyard market can't get out of it, and the investors who aren't in it don't want to be. Therefore, until a positive outlook becomes more conclusive, the overall market conditions will be slow to improve.