sinking thought
Also called laxity or sluggishness, sinking thought is a mental factor which causes the object of meditation to appear in a dull manner. Gross laxity is a dull and heavy mind which holds the object of meditation but lacks clarity and lucidity. Subtle laxity is a stable mind which holds the object of meditation clearly but lacks intensity. Sinking thought and scattering are the two main hindrances to single-pointed concentration. See also lethargy.