Likewise in the Synagoge (tau84) and Photius (tau141 Theodoridis), where however the headword participle is not the Suda's un-alphabetical teleou=nta -- suggested by Theodoridis as a conjecture by this compiler -- but telou=nta.
Glossed thus, it is neuter nominative/accusative plural, but note that Hesychius tau445 glosses it with tetagme/non, i.e. as masculine accusative singular. (Reference to a person might give better sense: cf. LSJ s.v. tele/w A.II.3.) Either way, there are numerous possibilities (beginning with Plato) for the source.