Sturdy farm building (6)
I believe the answer is:
stable
This clue is a double definition.
'sturdy' is the first definition.
(thesaurus)
'farm building' is the second definition.
(I know that stable is a type of farm building)
(Other definitions for stable that I've seen before include "Immutable" , "Maintaining equilibrium" , "Not likely to fail" , "Jesus was born in one" , "Settled; animal shed" .)