Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Coptŏs, i, f., = Κοπτός, Κοπτώ, a trading town in the Thebaid, on the eastern side of the Nile, afterwards Justinianopolis, now Coft, Plin. 5, 9, 11, § 60; Juv. 15, 28; Amm. 22, 16, 2; Itin. Ant. p. 165, 6 al.
Hence,