Donkey Crossing

Riddle: A traveler came to the river side, with a donkey bearing an obelisk. But he did not venture to ford the tide, for he had too good an *. What is the missing word?

Answer: Asterisk = "Ass to Risk". Source: https://www.riddles.com/3281

A traveler came to the river side, with a donkey bearing an obelisk. But he did not venture to ford the tide, for he had too good an *.
What is the missing word? — Donkey Crossing by don orr Riddle