In Arabic lexicography this term indicates ‘(a word) having two mutually exclusive meanings’ (pl. ʾaḍdād). The compilations concerning the ʾaḍdād pertain to the activity of collecting every aspect of the Arabic language undertaken by philologists from the end of 2nd/8th century onwards. The case of the ʾaḍdād, according to the Arab philologists, is a particular instance of the lexical category of the muštarak ‘the common one’, i.e. homonymous polysemic words, such as ʿayn ‘eye’, ‘source’, ‘coin’, and so on (cf. as-Suyūṭī [d. 911/1505], Muzhir I, 369–386), which in this particu…