anupalabdhiḥ
Means of knowing that which is non-existent - a pramāṇam; non-recognition.
In Vedanta
Non-apprehension — the pramāṇam that reveals the absence of something. One knows the pot is not on the table by looking and not seeing it. In Vedānta, this is relevant because mokṣa is understood as the absence of bondage (bandha-abhāva), not the gaining of something new. The recognition that there is no bondage is itself liberation.