Your options depend on how much code you can agree on. Ask about imaginary relatives map each name to a meaning, so asking about the health of Aunt Judy could mean that the prison refuses your access to a lawyer and telling you thought about Uncle Sam could mean they keep you in solitary. Or whatever facts you want to communicate. Your revolutionary friends could respond in the same manner. The flaw is in being limited to previously agreed upon code words.

If you have access to a common book, you can refer to words by page, line and word number. You could embed the numbers as words in a story you are writing to your (imaginary) child. “Behind the seven hills, there were five houses with nine rooms each” can translate to “take the 9th word on page seven, line five”. Obviously you need the exact same copy of the book for this to work, the Bible is quite common for this cipher.