a colloquial expression “дело десятое”

The colloquial expression “дело десятое” means:
1) Something non-essential, insignificant. It may be said, for example, about some unimportant details.
2) The most simple thing, the most simple part of a bigger affair.

This expression is only used in informal speech. There is a synonym which can also be used both in informal and in polite speech: “не суть важно”.

There are other expressions with similar (but not absolutely the same) meaning: Read the full text »