Resources for rare Qur’anic vocabulary include explanations reported through al-Ḍaḥḥāk, questions associated with Nāfiʿ ibn al-Azraq and the replies attributed to Ibn ʿAbbās, as well as later collections of lexical material.
Al-Suyūṭī incorporated discussions of gharīb vocabulary into al-Itqān fī ʿUlūm al-Qurʾān, situating lexical interpretation within the wider disciplines of Qur’anic studies.
The usefulness of a source does not establish that each individual explanation is beyond examination. Differences should be weighed through transmission, language, and context.