To leave is to go away or exit. You can leave the country, the house, or a job.
This has many meanings, most having to do with departing. Getting permission to take time off from work is taking a leave of absence. To not disturb something is to leave it alone. To abandon or forget something is to leave it behind. Giving someone leave to do something is giving them permission. Leaving can mean transmitting or passing on skills. Also, you can leave things to people in a will: you grandfather might leave you his favorite cufflinks.