[1] Same glossing in Photius and other lexica. The headword phrase contains the present middle participle, masculine nominative singular, of u(pote/mnw (cf. upsilon 401, upsilon 606, upsilon 608, etc.). See further, next note.
[2] In Xenophon, Cyropaedia 1.4.19, according to Adler -- but that passage contains only the future, third person plural, u(potemou=ntai (of a cavalry manoeuvre). Perhaps Adler's reference is simply a mistaken repetition of the one given under upsilon 605. In any event, for the headword phrase as a whole, see rather Xenophon Hellenica 1.6.15: "cutting off the voyage into Samos" (web address 1).