رَأَيْتُ أَسَدًا يَرْمِي
“I saw a lion shooting arrows.”
The activity of shooting is a contextual indicator excluding an actual animal. The resemblance between a lion and a courageous person in bravery supplies the basis for metaphor.
The important point is intended resemblance. A careless misnomer or a random naming does not become rhetorical metaphor merely because some incidental likeness could be discovered afterward.
Relation, contextual indication and intended communicative effect work together to determine the figure.