Likewise already in Hesychius (chi515) and again in later lexica, e.g. Etymologicum Magnum 812.34. The headword -- nominative/accusative neuter singular or masculine accusative singular of the adjective xlidano/s (cognate with chi 340, q.v.) -- must be quoted from somewhere but is not independently attested.
On the adjective itself, with early instances in lyric poetry (Sappho fr.60 Lobel-Page) and tragedy (Aeschylus, Persae 544), see generally LSJ s.v.