Same or similar entry in other lexica. Aorist infinitives. The headword one -- which can also be accented gru=cai -- is presumably quoted from somewhere; if so, extant possibilities include Isaeus (8.27), Herodas and Philostratus; note, however, that Latte on Photius s.v. cites instances of other forms of this verb in the Septuagint (Exodus 11.7, Joshua 10.21).
The verb gru/zw (already at gamma 462), especially common in comedy, literally means 'to make a sound like gru' (gamma 461).
cf. also gamma 464.