The fox borrows the tiger's ferocity (by walking in the latter's company 　 Bully others by flaunting one's powerful connections)

A tiger was looking for food in a large forest when a fox ran by. The tiger sprang forward and caught it.

The fox was frightened, but it had an idea in a blink. "You dare not eat me." it said.

"Why?" the tiger asked.

"I was sent by God to rule all the animals. If you eat me, you're disobeying the God's order. Then you're not a good animal."

The tiger kept silent for a moment, thinking whether it was true that the fox had been sent the god. Seeing the tiger still in doubt, the fox said seriously, If you don't believe me, I can show you how powerful I am. Just follow me round the forest and see if there's any animal that dares approach me."

So the fox led the tiger into the forest. It was true that all the animals, such as deer, sheep, and rabbits, etc., ran away as soon as they saw them.

The tiger did not know that all the animals ran away only because they were afraid of itself, while the fox just borrowed the tiger's terror and showed its authority before the animals.

The idiom comes from this fable. The story tells us that there is always someone who tries to swagger about in borrowed plumes.