Attendants keep losing a university key (7)
I believe the answer is:
retinue
'attendants' is the definition.
(I've seen this before)
'keep losing a university key' is the wordplay.
'keep' becomes 'retain' (retaining is a kind of keeping).
'losing' suggests deleting specific letters.
'university key' becomes 'ue' (I can't explain this - if you can you should believe this answer much more).
'retain' with 'a' taken out is 'retin'.
'retin'+'ue'='RETINUE'
Can you help me to learn more?
(Other definitions for retinue that I've seen before include "Train, following" , "Band of attendants" , "Body of followers" , "Cortege" , "Group of assistants" .)