The gap between 'syntax' (the formal rules) and 'semantics' (what's actually being done).
It's the observation that the official rulebook can hide the real strategy underneath it.
An organization's legal paperwork can look perfectly correct while its real operations point elsewhere, and demanding that the paperwork alone prove the true intent is a logical dead end.
It explains why 'but it's all technically legal' is such a powerful cover — the surface rules can never fully reveal the hidden game.