Noun
inner cabinet (plural inner cabinets)
The (often informal) inner circle within a cabinet (which may itself by an official inner circle within a government or council of ministers) which includes only the ministers (or secretaries of state etc.) who are closest to the executive head of state, prime minister or equivalent (notably presiding) officer
Our invisible governors are, in many cases, unaware of the identity of their fellow members in the inner cabinet. Edward Bernays