The hospital border? (5)
I believe the answer is:
hedge
'the hospital border?' is the definition.
'hedge' can be an answer for 'border?' (I have seen 'Border of vegetation ' mean 'hedge' so perhaps 'border' could also mean 'hedge'). I'm not certain of the 'the hospital' bit.
'hospital border?' is the wordplay.
'hospital' becomes 'h'.
'border?' becomes 'edge' (border is a kind of edge).
'h'+'edge'='HEDGE'
Can you help me to learn more?
(Other definitions for hedge that I've seen before include "Fence of bushes or small trees" , "Row of linked shrubs" , "Border of vegetation" , "Boundary of shrubs" , "sort of fund" .)