Congregation notice Priest around hospital (5)
I believe the answer is:
sheep
'congregation' is the definition.
(flock)
'notice priest around hospital' is the wordplay.
'notice' becomes 'see' (I've seen this before).
'priest' becomes 'p' (ecclesiastical abbreviation).
'around' means one lot of letters goes inside another.
'hospital' becomes 'h' (abbreviation for hospital on maps).
'see'+'p'='seep'
'seep' going around 'h' is 'SHEEP'.
(Other definitions for sheep that I've seen before include "(Meek) member of a flock?" , "Gregarious animal(s)" , "Farm animals" , "Woolly quadruped" , "Source of lamb" .)