Look up Queen's zoo employee (6)
I believe the answer is:
keeper
'zoo employee' is the definition.
(I've seen this in another clue)
'look up queen's' is the wordplay.
'look up' becomes 'keep' (I've seen this in other clues).
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'keep'+'er'='KEEPER'
(Other definitions for keeper that I've seen before include "penalties will come my way" , "Custodian; bar across magnet" , "Guardian, in the zoo say" , "Custodian, steward" , "Animal custodian; plain ring" .)