First ask whether the exact expression recurs or whether different morphological forms are involved. Where distinct forms belong to the same root, derivation is a more precise description than bare repetition.
When only sound or spelling resembles, consider jinās and quasi-derivation; the latter emphasizes an appearance of shared derivation without the genuine link.
Then verify the positional pattern. A lexical relationship by itself does not prove radd al-ʿajz ʿalā al-ṣadr.