Likewise or similarly in other lexica; references at Photius upsilon152 Theodoridis. The headword is aorist middle of u(poste/llw, first person singular. It must be quoted from somewhere: Acts of the Apostles 20.20, according to Adler (and others: see Theodoridis' note), but there are other possibilities, chiefly Demosthenes 19.338.
cf. upsilon 589 and esp. upsilon 590.