Usage: 4 forms in 9 verses
Form Translated As     In Verse(s)
προφυλακήσ advance guard LXX.Neh.4.23
post LXX.Exod.12.42
προφυλακήν an advance guard LXX.Ezek.26.8LXX.Ezek.38.7
προφυλακή a post LXX.Exod.12.42
an advance guard LXX.Num.32.17LXX.Neh.4.22
his own post LXX.Neh.7.3
προφυλακάσ advance guards LXX.Nah.2.5

Liddell-Scott-Jones

προφυλακή (prophulakē) an advance guard G:N-F

προφυλακή-ᾰκή, ,

guard in front; in plural, outposts, vedettes, piquets, [Refs 5th c.BC+] his advanced guard, [Refs 5th c.BC+]; ἀριστοποιεῖσθαι διὰ προφυλακήακῆς with an advanced guard, with outposts, [Refs 5th c.BC+]

__II guarding, guard, τῶν πόλεων [Refs 2nd c.BC+]
__III watch, vigil, [LXX]
__IV caution, προφυλακήακῇ χρῆσθαι περί τι [Refs 1st c.AD+]
__IV.2 precaution, c.genitive, against.., [προφυλακήακῆς χάριν">Refs 4th c.BC+] as a precaution, [Refs 1st c.AD+]

LSJ Scripture Refs: LXX.Exod.12.42