زَيْدٌ أَسَدٌ
Zayd is a lion.
In a discussion of bravery this does not literally change Zayd's biological species. It produces an emphatic image of his courage. The context, shared knowledge, and rhetorical purpose locate the intended attribution.
Without a relevant cue, the expression could become confusing. Rhetorical intensity therefore does not license unintelligible claims. Effective eloquence depends on the hearer recognizing the direction of the comparison.