Well-mannered; polite:he is always genteel and mannerly in private...
A more self-assured, unfailingly polite and mannerly man never existed.
Trying to approach this gentle and mannerly retired professor about what seems to be going wrong, Miller encounters the deep stubbornness at the core of his being.
These fine young gentleman were well-behaved and very mannerly.
Derivatives
mannerliness
/ˈmanəlɪnəs /noun...
It has concentrated on good morals and mannerliness in conduct.
On the contrary, eating too little implies a lack of mannerliness, which may vex the host.
And this, to my mind, is his distinctive failing as a writer: that he has exalted charm and mannerliness above all else.