Marfūʿ jinās involves a single expression resembling a sound sequence assembled from the end of one word and another complete word. The likeness is produced across a word boundary and may use only a part of the preceding word.
«أهذا مُصابٌ أم طَعْمُ صابٍ»
Is this a calamity, or the bitter taste of ṣāb?
The sounds of «مصاب» recur across the boundary in «طَعْمُ صابٍ»: the final mīm of ṭaʿm followed by the separate word ṣāb. In the first occurrence «مصاب» is a single word; in the second the comparable sound sequence straddles two words. This makes the case distinct from complete jinās between two independent simple words.