secret government business; internal government affair
Refers to matters handled confidentially within a government or administrative body, not disclosed to the public. Often used in contexts of bureaucratic discretion or behind-the-scenes decision-making.
The matter was handled as secret government business.
This is a case that should be kept as an internal government affair.
Compound of 内 (uchi, 'inside') and 沙汰 (sata, 'affair, matter'). The exact historical derivation is uncertain, but the term has been used in bureaucratic contexts to denote confidential government business.