النسخ — الإغارة — المسخ — الإلمام
Verbatim taking, verbal reworking, and borrowing of meaning.
Naskh/intihāl retains the earlier wording and arrangement to a substantial degree. Ighārah/maskh changes the verbal organization or takes some wording. Ilmām/salkh borrows the idea while rewording it.
These analytical categories do not by themselves prove a historical act of copying.