Usage: 2 forms in 2 verses
Form Translated As     In Verse(s)
διαμαρτάνοντεσ missing LXX.Judg.20.16
διαμάρτητε you should miss entirely LXX.Num.15.22

Liddell-Scott-Jones

διαμαρτάνω (diamartanō) to miss entirely G:V

διαμαρτάνω-άνω,

future -αμαρτήσομαι[Refs 4th c.BC+] —strengthened for ἁμαρτάνω, miss entirely, go quite astray from, τῆς ὁδοῦ [Refs 5th c.BC+]; τῆς ὀρθοτάτης πολιτείας [Refs 4th c.BC+]

__2 fail utterly of, fail of obtaining, τινός [Refs 5th c.BC+]; δυοῖν χρησίμοιν οὐ δ. not to miss both of two good things, [Refs]
__3 absolutely, fail utterly, opposed to τυγχάνω, [Refs 5th c.BC+]; to be quite wrong, [Refs 3rd c.BC+]; γνώμῃ in judgement, [Refs 4th c.BC+]; ἐν τῇ ἀρχῇ[Refs]:—passive, τὰ πολλὰ.. διημαρτημένα utter failures, [Refs 5th c.BC+]; διημαρτημένος faulty, of style, [Refs 4th c.BC+]. adverb διημαρτημένως [Refs 2nd c.AD+]