a·po·ri·a 
(ə-pôrē-ə)
(ə-pôrē-ə)n.
1. A figure of speech in which the speaker expresses or purports to be in doubt about a question.
2. An insoluble contradiction or paradox in a text's meanings.
[Greek aporiā, difficulty of passing, from aporos, impassable : a-, without; see A-1 + poros, passage; see per-2 in the Appendix of Indo-European roots.]