Definition - What does Arhat mean?
Arhat is a Sanskrit word that means “worthy,” “venerable” and “deserving.” In Theravada Buddhism, an arhat is defined as one who has reached a state of nirvana through extreme self-discipline and abstention from worldly pleasure.
Depending on the school of Buddhism and the evolution of the term over the centuries, arhats may be considered as similar to buddhas, or enlightened ones. Some traditions, like Mahayana Buddhism, consider arhats imperfect when compared to buddhas. In contrast, the Pali Tipitaka text describes arhat as the goal of the buddha's path to liberation.
Yogapedia explains Arhat
Some early scriptures refer to the historical Buddha, or Siddhartha Gautama, as an arhat. Theravada Buddhists believe that all enlightened beings are arhats, but that just one in each eon is a buddha — distinguished by his learning and ability to teach others.
In Mahayana Buddhism, arhat may describe an enlightened being or a Buddhist who is spiritually advanced, but has not reached buddhahood.
In Tibetan and Chinese Buddhism, arhats are revered like saints. They are believed to have been chosen from the Buddha's disciples to remain in the world and protect the dharma.