قاتل زيد عمراً — Zayd fought ʿAmr.
جاءني زيد وعمرو — Zayd and ʿAmr came to me.
The first conveys interaction between two participants; the second reports that two people share the action of coming. Neither fact alone means that one individual has been represented as resembling the other.
In technical simile, shared meaning functions as a rhetorical comparison. Merely reporting participation in an act serves a different purpose. We therefore cannot apply the technical definition to every grammatical occurrence of shared action or meaning.