Sounder of warning up to now about hospital (6)
I believe the answer is:
shofar
'sounder of warning' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'up to now about hospital' is the wordplay.
'up to now' becomes 'sofar' (I've seen this in another clue).
'about' is an insertion indicator.
'hospital' becomes 'h' (abbreviation for hospital on maps).
'sofar' going around 'h' is 'SHOFAR'.
Can you help me to learn more?
(Other definitions for shofar that I've seen before include "Ram's horn trumpet" , "one would rally people to battle" , "Wind instrument" .)