كتشبيه الخد بالورد
As in likening a cheek to a rose.
The subject is the cheek and the comparison term is the rose. Neither is restricted here by an additional circumstance integral to the comparison. Depending on context, the shared respect may be colour, delicacy, or freshness.
“Unrestricted” does not mean lacking any imaginable qualities. It means the expression does not attach a special condition or relation whose removal would change the simile. In this case, the cheek and the rose suffice as the two compared terms.