The headword is aorist middle, first person plural, of proi+/hmi. It must be quoted from somewhere -- perhaps Demosthenes 5.13 (polla\ ga\r proei/meqa, w(=n u(parxo/ntwn to/t' a)\n h)\ nu=n a)sfale/steros kai\ r(a|/wn h)=n h(mi=n o( po/lemos), where in context it could reasonably be explained by the present, present-tense gloss.
cf. generally pi 2394, pi 2417, pi 2422, pi 2428, pi 2549.