"yo pana bhikkhu anupasampannassa uttarimanussadhammaṃ āroceyya, bhūtasmiṃ pācittiyaṃ."
Not to announce to a layman a realisation that has been achieved. If a bhikkhu announces to a layman or to a sāmaṇera, a realisation partaking with a jhāna nature or with a stage of ariyā, and this realisation has genuinely been achieved, he commits a pācittiya.
On the other hand, a bhikkhu who makes such a declaration, while knowing it to be false, commits the pārājika 4. A bhikkhu must avoid making his attainments known, even to other bhikkhus. Apart from four exceptions when they can do so, ariyās never unveil their realisations: