tacit understanding; unspoken agreement
A mutual understanding that is not explicitly stated but is implicitly shared among the parties involved. Often used in social, business, or diplomatic contexts.
By tacit understanding, they avoided touching on that topic.
There is an unspoken agreement in the team that overtime is left to each person's discretion.
暗黙の了解 is a more casual, everyday phrase for a tacit understanding, while 不文律 sounds more formal and rule-like.
Compound of 暗黙 (あんもく, 'tacit, implicit') + の (possessive particle) + 了解 (りょうかい, 'understanding, agreement'). The phrase is a direct combination of these elements and is not derived from a single classical source.