Thank you to Malcolm Rigg for pointing out that ‘my mother-in-law is formidable’ becomes a compliment in French. Put the stress on the third syllable, and the French ‘formidable’ instantly transforms your mother-in-law to: amazing, fantastic, tremendous.
If Malcom Rigg sends me his postal address I shall get a copy of “False Friends: Faux Amis: Book Two” (hot off the press) off to him free, gratis and for nothing.