brains trust
noun[C]
UKold-fashionedukus(USbrain trust)agroupofexpertswho giveadviceto aleaderororganization,especiallyadvicerelatingtoplanning:
Abrainstrustofscientistswillstaffthe university's newbiosciencesinstitute.
Hebecamepartof the president'sbraintrustduring his firstpresidentialcampaign.