From 'adar; wide or (generally) large; figuratively, powerful -- excellent, famous, gallant, glorious, goodly, lordly, mighty(- ier one), noble, principal, worthy.
see HEBREW 'adar
H117. addir
אַדִּיר adjective majestic — ׳א Psalm 8:2 +; feminine אַדֶּ֫רֶת Ezekiel 17:8 ? (see below) etc. —
1 majestic (wide, lofty) of waters of sea Exodus 15:10; Psalm 93:4; a ship Isaiah 33:21; a tree Ezekiel 17:23; a vine 17:8 (אַדֶּרֶת גֶּפֶן, so Fü; or ׳א abstract noun see below אַדֶּרֶת below); also figurative of kings Psalm 136:18; nations Ezekiel 32:18; gods 1 Samuel 4:8; of ׳י Psalm 93:4; 76:5; of name of ׳י 8:2; Psalm 8:10.
2 substantive majestic one, of nobles, chieftains, etc., Judges 5:13, 25; Nahum 2:6; 3:18; Jeremiah 14:3; 25:34 (הַצּאֹן אַדִּירֵי figurative so): 35.36; 30:21; Zechariah 11:2; 2 Chronicles 23:20; Nehemiah 3:5; 10:30; of ׳י Isaiah 10:34; 33:21; of servants of ׳י Psalm 16:3 (= priests ? compare 1 Chronicles 24:5 & see Che).