to gird: to bind a belt or garment around the waist, and so to arm or equip someone with what they need
TranslatabilityApproximateCertaintySettled
The core picture is simple and physical: fastening a belt or wrapping a cloth tightly around the waist. In the ancient world a loose robe had to be bound up before a person could run, fight, or work hard, so "girding" became shorthand for getting ready for effort. The command to gird the loins, which this word shares with its close relative חָגַר, belongs to that world of tucked-up garments and readiness for action.
From that literal act the word stretches naturally in several directions:
literal wearing, as when a man is described as girded with a leather belt
bracing for a demanding task, the sense behind "gird up your loins"
arming oneself for battle, taking on what a fight requires
being clothed with a quality one did not have, most often strength given by God
What holds these together is the idea of putting something on so tightly that it becomes part of how you stand and move. When God "girds" a person with strength, the strength is fastened to them like a belt they now carry into battle. When God himself is said to be girded with might, his power is pictured as something worn, ready, and secure. This is why the word crosses so easily from clothing to character.
Nuances
1ato put on or wear a belt; to bind a garment tightly around the body
TranslatabilityDirect
2Ki 1:8Job 30:18*
1bto gird up the loins: to brace oneself and get ready for strenuous action
Job 38:3Job 40:7Jer 1:17
1cto arm or equip oneself, especially for battle
Isa 8:9 (2×)Isa 50:11*
1dto clothe or endue with a quality such as strength, might, or gladness; often with God as the one who girds
reaches beyond clothing to being equipped by God with strength or mightPsa 18:32Psa 93:1
Both
both name binding a belt or garment tightly around the waist2Ki 1:8
Only gird
"gird" now sounds archaic and almost purely physical, so English readers can miss the sense of being given a quality
“arm”
Comparison data is not available for this English gloss yet.
“strengthen”
Comparison data is not available for this English gloss yet.
How azar differs from similar Hebrew words
חָגַרthe common everyday verb for strapping on a belt, sword, or sackcloth; this word leans more poetic and more often figurative, especially being girded with God-given strength.
Most often it is God who does the girding, equipping a person with strength for battle or for a task, so the picture is one of being supplied with power from outside.Psa 18:39Psa 18:322Sa 22:40
It describes God himself as girded, clothed in might and majesty the way a warrior or king straps on his power.Psa 93:1Psa 65:6
In the command to brace the body for hard effort, the readiness it calls for is inward resolve, summoning a person to stand and answer rather than to put on a literal garment.Job 38:3Job 40:7Jer 1:17
Both
Both can name binding the waist for action, the gesture of getting ready to move or fight, though one word leans figurative and the other concrete.Job 38:3Exo 12:11
It is the ordinary verb for physically putting on clothing and belts, used for the priests being dressed in their sashes and robes.Exo 29:9Lev 8:7Lev 8:13
It is the standard word for strapping on a sword to go armed, naming the literal act of fastening a weapon to the body.1Sa 17:391Sa 25:13Jdg 3:16
It commonly describes wrapping the body in sackcloth as a sign of grief and mourning, an everyday gesture of putting on coarse cloth.Jer 4:8Jol 1:8Lam 2:10
azar in the other biblical languages
περιζώννυμιGreek“to gird”the standard Greek verb for girding the waist, carrying the same "gird your loins for readiness" idiom into the New Testament.
Regularly means to arm someone with strength for battle, with God as the one who does the girding, so the belt becomes a picture of power given.2Sa 22:40Psa 18:391Sa 2:4
Can describe God himself as clothed with strength and majesty, the belt now a mark of his own might.Psa 65:6Psa 93:1
Extends to being clothed with an inner quality such as gladness, well beyond any literal belt.Psa 30:11
Both
Both name the plain act of strapping a belt around the waist so loose clothing is out of the way and the person is ready for work or a journey.2Ki 1:8Eph 6:14
Both are used as a call to brace oneself and be ready to act, girding the waist as a signal of readiness.Jer 1:17Luk 12:35
Pictures a servant tucking up his robe to wait on others at table, the posture of one ready to serve rather than to fight.Luk 12:37Luk 17:8
Describes a garment fastened high across the chest with a golden band, worn by the glorified figure and the angels, not only a belt at the waist.Rev 1:13Rev 15:6
What scholars say about azar
The lexica (BDB; HALOT) treat אזר as a single verb "to gird, gird oneself," attested in qal, niphal, piel, and hithpael, with a settled semantic range running from the literal binding of a belt or loincloth, through the fixed idiom "gird up the loins" for readiness (Job 38:3; 40:7; Jer 1:17), to the figurative endowing of a person with strength or might, most often with God as agent (Ps 18:32, 39; Isa 45:5). The word overlaps heavily with the more frequent חגר, and the two are near-synonyms; אזר is the more markedly poetic term and dominates the Psalms' language of divine strengthening. The noun אֵזוֹר "waistcloth" is cognate. No sense of the verb is genuinely contested.