叶公好龙
yè gōng hào lóng

There once was a man named Ye Gong and boy did he love dragons! Dragons everywhere – pictures in his house, embroidered dragons in his clothes, painted dragon murals on his walls, carved dragons figures on his shelves… some people say he even started to look like a dragon with his whiskers and bushy eyebrows.

One day the king of the dragons heard about Ye Gong. He was chuffed that a human could like dragons so much and decided to pay him a visit. He flew down from the sky, cutting a magnificent figure against the sunset sky as he approached Ye Gong’s house.

A window was open on the top floor of Ye Gong’s house, and after alighting on the earth the king of the dragons stretched his sinuous neck forward and poked his face inside, happy to finally meet his biggest fan.

However, when Ye Gong heard a noise behind him and turned around, instead of joy and happiness at seeing a real dragon all the colour drained from his face and he ran, screaming, down the stairs and locked himself in a small broom cupboard. Puzzled, the king of the dragons waited for a while and then sadly gave up and flew off back to the sky.

So the meaning of this idiom is that someone’s words and actions can differ markedly. I would translate this along the lines of “all mouth, no trousers”.

How would you express this idiom?