From ܩܲܕܝܼܡܵܐ (qadīmā, “preceding; old”) + -ܝܐ (-āyā, the attributive adjective ending).
ܩܲܕܝܼܡܵܝܵܐ • (qadīmāyā) (feminine ܩܲܕܝܼܡܵܝܬܵܐ (qadīmāytā), plural ܩܲܕܝܼܡܵܝܹ̈ܐ (qadīmāyē))