Mrs Grundy 
noun (plural Mrs Grundys)
A person with very conventional standards of propriety.Following hot on the re-banning of Pasolini's film ‘Salo’, the Mrs Grundys have revisited the 1978 horror flick, ‘I spit on your grave’ and have banned it....
- When will these latter-day Mrs Grundys realise that the only outcome of their hysteria is to massively increase the audiences for the object of their hand-wringing and breast-beating?
- The Mr and Mrs Grundys who are worried about the ‘poppy show’ might like to consider that serious physical activity, including traditional play, needs appropriate clothing, and school uniforms need to consider these requirements.
Origin
Early 19th century: a person repeatedly mentioned in T. Morton's comedy Speed the Plough (1798), often in the phrase ‘What will Mrs Grundy say?’, which became a popular catchphrase.