1) Arrest 2) Clap in jail 3) Confine 4) Confine as if in a prison 5) Detain 6) French word used in English 7) Gaol 8) Hold 9) Hold in custody 10) Hold prisoner 11) Immure 12) Impound 13) Incarcerate 14) Intern 15) Jail 16) Keep under lock and key 17) Lock up 18) Put away 19) Put behind bars 20) Put in jail Found on https://www.crosswordclues.com/clue/imprison
Im·pris'on transitive verb [ imperfect & past participle Imprisoned ; present participle & verbal noun Imprisoning .] [ Middle English enprisonen , Old French enprisoner , French emprisonner ; prefix en- (L.... Found on http://www.encyclo.co.uk/webster/I/24
incarcerateverb lock up or confine, in or as in a jail; `The suspects were imprisoned without trial`; `the murderer was incarcerated for the rest of his life` Found on https://www.encyclo.co.uk/local/20974