mannerly

/ˈmænərli/
adjective
  1. Having or showing good manners; polite and respectful.
    • The mannerly boy held the door open for the elderly woman.
    • The students were praised for their mannerly behavior during the field trip.
    • It is mannerly to say 'please' and 'thank you' when making requests.
adverb
  1. In a polite and well-mannered way.
    • He mannerly declined the offer, thanking the host for the invitation.
    • She mannerly greeted each guest at the reception.
    • The children ate mannerly, using their napkins and utensils correctly.