Ἰλλυρικοῖς

Ἰλλυρικός, of Illyria

Morpho works with a static database. If you like, you can compare the output of Morpheus.

Parsed as:

proper-name adjective masculine dative plural (cp Ἰλλυριοί)
proper-name adjective neuter dative plural (cp Ἰλλυριοί) of Ἰλλυρικός