The headword is the aorist infinitive of the middle-voice verb promhqeu/omai, a variant of promhqe/omai I am mindful beforehand; cf. pi 2505, pi 2509, and see generally LSJ s.v. The entry is carried over from prior lexicography: see next note. The source of the headword itself is uncertain; extant possibilities, all very late, include St. Nicholas I (Mystic), Epistles 56.11 (Jenkins and Westerink).
[1] The gloss is the same form as the headword, but from the verb pronoe/w, I perceive beforehand, foresee; see generally LSJ s.v. The headword is identically glossed in the Synagoge, Photius' Lexicon (pi1262 Theodoridis), and Lexica Segueriana 349.22.