ulterior motive

taka-ajatus An alternative or extrinsic reason for doing something, especially when concealed or when differing from the stated or apparent reason.
1895, w:Arthur_Conan_Doyle Sir Arthur Conan Doyle, The Stark Munro Letters, ch. 9,

There lurks no bribe in the smell and beauty of the flower. Its charm has no ulterior motive.

The poet is a man without a profit or any other kind of ulterior motive.