Behaviour which is contrary to social expectations, which is inappropriate or rude.(noun)
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Use "bad form" in a sentence
"Free-thinking and neglect of religious duties are at present considered the acme of bad form in Germany."
"Well, it would have been damned bad form to stay, and I swear to God I couldn't have — not without committing the fearful lèse-majesté of plunging into the mêlée crying "Me, too!""
"It has been objected that the people are incompetent to rule themselves; but Sismonde most truly says, "If pure democracy is a bad form of government, representative democracy cannot be worth more.""