Definition of "benison"

Poor old men! how could they be cordial with their sore consciences and shamed faces? how could they bid God bless him with hearty voices and a true benison, knowing, as they did, that their vile cabal had driven him from his happy home, and sent him in his old age to seek shelter under a strange roof-tree?

1855, Anthony Trollope, The Warden, page 197