onager

1. Put an onager in a city and sally forth when someone attacks, you can destroy them without them attacking you.
   在城里放个弩炮，当有人攻城时，出击，他们打不到你，而你能打到他们。

noun

1. Asiatic wild ass

   Synonym:    Equus hemionus

2. an engine that provided medieval artillery used during sieges

   Synonym:    catapultarbalestarbalistballistabricolemangoneltrebuchettrebucket