In its broad lexical use, tashbīh means establishing likeness between two things. The everyday sense of resemblance is wider than the category used for technical rhetorical analysis.
In rhetoric, technical tashbīh is a specific act of indicating shared meaning. Merely mentioning two things with one shared action is not sufficient. The technical category is distinguished from forms such as explicit metaphor, metaphor by allusion, and tajrīd (abstraction).
Examples:
“Zayd ka-l-asad fī al-shajāʿah” — Zayd is like a lion in courage: an explicit simile.
“Jāʾa Zaydun wa-ʿAmr” — Zayd and ʿAmr came: a shared event, but not automatically a simile.
This distinction prevents every expression of shared activity from being misclassified as a rhetorical comparison.