Dullness 昏沉 (Tib. བྱིང་པ་, Wyl. bying pa), together with agitation 掉舉, is one of the five faults 五過失 to meditation 禪修. Both in their subtle and gross form they are obstacles during the actual practice of meditation.
- Sogyal Rinpoche, A Treasury of Dharma (Lodeve: Rigpa, 2005), pages 184-186.