Visuddhimagga XXI-123

Rāgādīhi panesa suññattā suññato, rūpanimittādīnaṃ rāganimittādīnaññeva vā abhāvena animitto, rāgapaṇidhiādīnaṃ abhāvato appaṇihitoti idamassa saguṇato nāmaṃ.

（三）这（道）是由于贪等的空故为空。由于没有色相等或贪相等故为无相。由于没有贪愿等故为无愿。这是以（此道的）自德为名。

Ñ(XXI,123): 3. It is void because void of greed, and so on. It is signless owing either to absence of the sign of materiality, etc., or to absence only of the sign of greed, and so on. It is desireless because of absence of desire as greed, and so on. This is its name according to its own special quality.