Enquires about missing one rook and other pieces (6)
I believe the answer is:
queens
'pieces' is the definition.
(queen is a kind of piece)
I don't understand the remainder of the clue.
(Other definitions for queens that I've seen before include "Borough of NYC for the royals" , "[COLLEGE] < Tennis club" , "NY borough; two Oxbridge colleges" , "Most powerful pieces in chess games" , "Female monarchs" .)