noun
grey official; high official suspected of corruption
A metaphorical term for a senior bureaucrat or official who is suspected of corruption or shady dealings, but not yet publicly exposed. The 'grey' implies a lack of transparency, as opposed to 'black' (clearly corrupt) or 'white' (clean).
その灰色高官は、長年にわたり業界との癒着が噂されていた。
That grey official had long been rumored to have collusive ties with the industry.
灰色高官の存在が、政治不信をさらに深めている。
The existence of grey officials is further deepening distrust in politics.
Compound of 灰色 (grey) and 高官 (high official). The metaphorical use of 'grey' to indicate something neither clearly clean nor clearly corrupt is a modern extension, likely influenced by similar color metaphors in political discourse.