His eyes were hollows of madness, his hair like moldy hay, But he loved the landlord's daughter,
The landlord's red-lipped daughter,
Dumb as a dog he listened, and heard the robber say--

The poet’s use of figurative language in this stanza suggests he thinks the subject (the ostler)...

is unworthy of the love of the landlord’s daughter.

would be a good robber.

doesn’t appreciate the landlord’s daughter.

is more handsome than the highwayman