In implicit metaphor (isti'ara makniyya), the subject remains, the comparison model is omitted, and some characteristic or associated feature of the missing model points to it.
The borrowed comparison is therefore not always a single overt noun standing for another noun. It can be suggested by attributing a characteristic of a different kind to the expressed subject.
The associated feature that makes the imagined comparison perceptible is discussed as the imaginal (takhyiliyya) element.