From Longman Dictionary of Contemporary Englishdecorousdec‧o‧rous /ˈdekərəs/ adjective POLITE formal having the correct appearance or behaviour for a particular occasion —decorously adverb A servant was hovering decorously behind them.
Examples from the Corpus
decorous• It was normal for women to write about love, but they were expected always to be decorous.• He frequently attended church, and demanded strict attention and decorous behaviour from his court while at worship.• Above the decorous chat, the familiar bray of Peregrine's voice could be heard.• Safe Home Counties seats in the 50s wanted decorous ex-public schoolboys.• Naturally no expression of that shows through the decorous playfulness of her letters to him.• The Galleries will bridge the snarling ring road, which will be buried in decorous tunnels.• Two days later a more decorous visitor called.• The man had never behaved towards her in other than a friendly and decorous way; nevertheless, she burned.Origin decorous (1600-1700) Latin decorus, from decor “beauty, gracefulness” 