dig, fail, keep (rank), lack

Concise Bible Dictionary:

A trait in disciplined troops, expert in war (1 Chron. 12:33).

Strong’s Dictionary of Hebrew Words:

Number:
5737 (find all occurrences in KJV Bible)
Transliteration:
`adar
Phonic:
aw-dar’
Meaning:
a primitive root; to arrange, as a battle, a vineyard (to hoe); hence, to muster and so to miss (or find wanting)
KJV Usage:
dig, fail, keep (rank), lack