In Buddhism and Advaita Vedanta, conceptual proliferation (Pāli: papañca; Sanskrit: prapañca) or, alternatively, mental proliferation or conceptual elaboration, refers to unbounded conceptualization, "tend[ing] to obscure the true state of affairs."

The word prapanca (Sanskrit: प्रपञ्च) means "visible world," "manifoldness of form," "expansion of the universe." According to Mayrhofer, prapanca originally meant an 'endless exposition' ("weitläufige Auseinandersetzung"), as well as "counting on five fingers."

The translation of papañca as conceptual proliferation was first made by Katukurunde Nyanananda Thera in his research monograph Concept and Reality (1971).

Andrew Olendzki explains that:

P[r]apanca is "the tendency of the mind to 1) spread out from and elaborate upon any sense object that arises in experience, smothering it with wave after wave of mental elaboration, 2) most of which is illusory, repetitive, and even obsessive, 3) which effectively blocks any sort of mental calm or clarity of mind."

Aprapanca is "(that which is) beyond discursive thinking," as stated in the Gaganagañjaparipṛcchā, the eighth chapter of the Mahāsaṃnipāta Sūtra.

Nisprapapanca/'nippapañca is the stopping of discursive thought or conceptualisation. Buswell and Lopez explain nisprapanca as follows:

"conceptual nonproliferation" or "absence of superimposition," the transcendent (lokatara) state of mind that is characteristic of the enlightened noble person (ĀRYA). Nisprapañca refers to the absence of that which is fanciful, imagined, or superfluous, especially in the sense of the absence of a quality that is mistakenly projected onto an object. This false quality is called PRAPAÑCA [...] In the YOGĀCĀRAschool of Mahāyāna Buddhism, nisprapañca refers to the absence of the misapprehension of sensory objects as separate from the perceiving consciousness, and in the MADHYAMAKA school it refers to the absence of perceiving objects as endowed with SVABHĀVA.