incommunicado
adverb or adjective
in·com·mu·ni·ca·do ˌin-kə-ˌmyü-nə-ˈkä-(ˌ)dō 
: without means of communication : in a situation or state not allowing communication
a prisoner held incommunicado
remained incommunicado while working on her book
Did you know?
Incommunicado ultimately comes from Latin but made its way into English via the Spanish incomunicado. We borrowed the word (with a slightly modified spelling) from the past participle of the Spanish verb incomunicar, meaning "to deprive of communication." The Spanish word, in turn, derives from the Latin prefix in- and the verb communicare, meaning "to communicate."
Example Sentences
Recent Examples on the Web Most of those detained during and after the demonstrations are young people from the poorest corners of the country who have been held incommunicado, relatives say. 
Santiago Pérez, WSJ, 20 July 2021
Santiago Pérez, WSJ, 20 July 2021 Word History
Etymology
Spanish incomunicado, from past participle of incomunicar to deprive of communication, from in- (from Latin) + comunicar to communicate, from Latin communicare
First Known Use
1844, in the meaning defined above