"The Worthy One"; living person who has reached Enlightenment. In Theravada Buddhism, an arhat (Sanskrit; Pali: arahant-; "one who is worthy") is a "perfected person" who has attained nirvana. In other Buddhist traditions the term has also been used for people far advanced along the path of Enlightenment, but who may not have reached full Buddhahood.
The understanding of the concept has changed over the centuries, and varies between different schools of buddhism and different regions. A range of views on the attainment of arhats existed in the early Buddhist schools. The Sarvāstivāda, Kāśyapīya, Mahāsāṃghika, Ekavyāvahārika, Lokottaravāda, Bahuśrutīya, Prajñaptivāda, and Caitika schools all regarded arhats as being imperfect in their attainments compared to buddhas.
Mahayana Buddhists are urged to take up the path of a bodhisattva, and to not fall back to the level of arhats and śrāvakas. The arhats, or at least the senior arhats, came to be widely regarded as "moving beyond the state of personal freedom to join the Bodhisattva enterprise in their own way".
In Mahayana Buddhism, a group of Eighteen Arhats with names and personalities were regarded as awaiting the return of the Buddha as Maitreya, and other groupings of 6, 8, 16, 100, and 500 also appear in tradition and Buddhist art, especially in East Asia. They can be seen as the Buddhist equivalents of the Christian saints, apostles and early disciples and leaders of the faith.