inseparable

/ɪnˈsɛpərəbəl/
adjective
  1. Unable to be separated or parted; very closely connected.
    • In many cultures, music and dance are inseparable art forms.
    • The two friends have been inseparable since kindergarten.
    • For the chef, fresh herbs are inseparable from a good pasta sauce.
  2. (of a pair or group) always together; extremely close in relationship.
    • In the movie, the hero and his sidekick are inseparable partners.
    • My dog and I are inseparable; he follows me everywhere.
    • The twins were inseparable during their school years.