Lewis & Short

in-dissŏcĭābĭlis, e, adj., inseparable (eccl. Lat.): unitas, Lact. Opif. D. 10; Ambros. Ep. 14.
Adv.: indissŏcĭābĭlĭter, inseparably, Claud. Mam. Stat. Anim. 1, 18.