Metaphor borrows the word for one thing and applies it to another. That transfer has force because a point of resemblance is understood between them. Simile consequently provides the conceptual basis for understanding metaphor.
Simile: “Zayd ka-l-asad” — Zayd is like a lion.
Metaphor: “Raʾaytu asadan yarmī” — I saw a lion shooting arrows. If the context identifies a brave human archer, the term “lion” is borrowed figuratively.
Both involve likeness but express it in different linguistic ways. Technical simile explicitly indicates a shared quality; metaphor transfers a name across the comparison.