adult reasons; certain circumstances; professional constraints
Euphemistic phrase used when the real reason cannot be disclosed, often implying behind-the-scenes or organizational considerations. Similar to 大人の事情.
See also: 大人の事情
The project was canceled due to certain adult circumstances.
I can't go into details, but it was decided for adult reasons.
Nearly synonymous; 大人の都合 is slightly less common and may emphasize scheduling or convenience, while 大人の事情 is more general.
Compound of 大人 (adult) + の (possessive particle) + 都合 (circumstances, convenience). The phrase is a modern euphemism, not derived from classical sources.