Mention hospital with nothing in till (6)
I believe the answer is:
plough
'till' is the definition.
(ploughing is a kind of tilling)
'mention hospital with nothing' is the wordplay.
'mention' becomes 'plug' (I have seen 'Favourable mention ' mean 'plug' so perhaps 'mention' could also mean 'plug').
'hospital' becomes 'H' (abbreviation for hospital on maps).
'with' indicates putting letters inside.
'nothing' becomes 'O' (O resembles 0).
'plug'+'h'='plugh'
'plugh' going around 'o' is 'PLOUGH'.
'in' is the link.
(Other definitions for plough that I've seen before include "Furrower of soil" , "Furrow cutter" , "Soil churner" , "Soil-breaker" , "that produces agricultural turnover" .)