From SuspireWiki

(adj., informal/formal) Involved in business; a part of the team; preoccupied. Typically, this phrase is used when referring to business, meetings, or operations which are best left undisclosed to present company.

Very sorry, but Master cannot see you now as he is at the table with the Priscus. Or, You’re going to have to do better than that, Jonas, if you want a seat at the table.