المرسل
A figurative transfer not restricted to one particular relation of resemblance.
Istiʿārah is tied to similarity. Mursal permits a range of other relations: cause/effect, part/whole, place/inhabitant, instrument/effect, former state or anticipated outcome. The name reflects this plurality of admissible connections.
“Mursal” does not mean unregulated speech. Each example still requires a recognizable and valid semantic relation. The variety concerns the kinds of relation available, not permission to make arbitrary substitutions.