Arhat:
This is pious word in both Jainism And Buddhism. Chinese , Sanskrit and Pali Language.
It means the most highest being.Arhat  reached the state of Nirvana and are free of worldly cravings.

The Eighteen Arhats are depicted in Mahayana Buddhism as the original followers of the Buddha who have followed the Eightfold Path and attained the Four Stages of Enlightenment. They have reached the state of Nirvana and are free of worldly cravings.

The four stages of enlightment

The four stages are 

A Stream-enterer (Sotapanna) is free from:

1. Identity view(me and mine)

2. Attachment to rites and rituals(following morals)

3. Doubt about the teachings(who believes in Dharma totally)

B. Once-returner (Sakadagami) has greatly attenuated:

4. Sensual desire

5. Ill will

C. Non-returner (Anāgāmi) is free from:

4. Sensual desire

5. Ill will

An Arahant is free from all of the five lower fetters or sin and the five higher fetters, which are:

6. Craving for fine material existence

7. Craving for existence on the level of formlessness

8. Conceit

9. Restlessness

10. Ignorance