رَأَيْتُ أَسَدًا يَخْطُبُ
I saw a lion delivering a sermon.
If the intended referent is a brave man, asad is transferred from the animal to that person. Yakhṭubu provides a clue that the intended referent is human. The borrowed term names the comparison vehicle explicitly, so this is an explicit metaphor (istiʿārah taṣrīḥiyyah).
In “Zayd is like a lion,” both compared terms are expressed and the statement is a simile. Treating these structures as interchangeable would erase a central distinction.