Ignoring nurse initially, doctor inspects dirty pool (7)
I believe the answer is:
cesspit
'pool' is the definition.
(cesspit is a kind of pool)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for cesspit that I've seen before include "Sewage holder" , "means of waste disposal" , "Foul and squalid place" , "Sewage storer" , "Sewage receptacle" .)