I would like to ask native speakers a question about the adjective "duteous", which I found in Shakespeareīs "Othello". In The Free Dictionary, which is a compilation of several high-quality dictionaries, it is evaluated as "archaic and formal" in one entry (The Collins Dictionary), and not stylistically classified in other entries. According to Google search engine, the adjective "dutiful" occurs like ten times more often (I didnīt use specialized language copora).

My point is: isnīt it too formal, old-fashioned or perhaps even ridiculous (esp when used by a learner of English as a foreign language, whose speaking or writing skills are generally far from perfect)? Or is it still usable as a standard expression at least in written English?