The headword is perfect middle/passive participle, masculine nominative singular, of the verb dioiki/zw (cf. delta 1230). Evidently quoted from somewhere (perhaps Philo Judaeus, Quis rerum divinarum heres sit 83). The headword and gloss, without the syntactical comment, occur in Synagoge delta326, Photius delta682, and (in the plural) Hesychius delta2044. Adler also cites Lexicon Ambrosianum 703 for the lemma and gloss, and the Lexicon Syntacticum of Codex Laurentianus 59.16 for the syntactical addendum.
For such a participle cf. generally e.g. [Lucian], Charidemus 19 o(/sous tou= tau/ths [sc. th=s (*ippodamei/as] ka/llous a(lo/ntas ma/llon ai)roume/nous a)pe/fhnen a)poqnh/skein h)\ tau/ths diw|kisme/nous to\n h(/lion prosora=n; "those captured by her beauty, Hippodamia induced to choose to die rather than to keep seeing the daylight, but separated from her".