The term 'in a proper manner' can be expressed in several ways, such as fitly (5 letters), DULY (4 letters), formally (8 letters), NICELY (6 letters), DECENTLY (8 letters), and decorously (10 letters). Fitly means to do something in an appropriate or suitable way, while DULY implies doing something in a timely or punctual manner. Formally suggests doing something in an official or ceremonious way, while NICELY implies doing something in a pleasant or agreeable way. DECENTLY implies doing something in a respectable or honorable way, and decorously suggests doing something in a manner that is socially acceptable.