in ‧ most /ˈɪnməʊst $ -moʊst/ BrE AmE adjective [only before noun]
1 . your inmost feelings, desires etc are your most personal and secret ones:
In his inmost heart, he knew he didn’t love me.
2 . formal furthest inside a place, and so difficult to see or find:
Apparently there are bats in the inmost caves.