Apratiṣṭhita nirvāṇa, nirvāṇa without abode, is the Mahāyāna description of a buddha’s attainment: through wisdom it does not abide in saṃsāra, and through compassion it does not abide in a quiescent nirvāṇa, but continues to work for beings.
Non-abiding nirvāṇa
The Mahāyāna nirvāṇa that dwells neither in saṃsāra nor in a passive peace, but acts in the world.
Also: apratishthita nirvana