1. off the grid - Adjective
2. off the grid - Adverb
(of a home, business, or the occupants thereof) Not using electricity from the public electrical supply system.
Not connected to a publicly available communication system, such as the World Wide Web or a mobile telephone network.
(idiomatic) Isolated; in a remote location; in seclusion; not participating in some official process or system.
In or into a situation or place in which electricity from the public electricity system is not used.
(idiomatic) In or into a clandestine or isolated situation or place, especially one in which public communication is curtailed.
(idiomatic) Secretly; in a clandestine manner.
Source: en.wiktionary.orgoff-the-grid