Related Clues:
- Prefix meaning 'inside'
- Prefix denoting outer
- Prefix with skeleton or plasm
- Prefix with -dermal
- Nothing to write home about?
- It means ''outer''
- Known to few
- Cloak-and-dagger
- Like some documents
- Like some handshakes
- Prefix with -morphic
- It's not to be told
- Confidential, not to be revealed
- Private, hidden
- The inside of anything