Outer may describe the outside court of the temple. In the phrase “outer darkness,” it portrays the darkness and exclusion associated with the judgment of the lost.
Definition
Outer is an adjective meaning outside or farther outward. It may describe the outside court of the temple or, in the phrase “outer darkness,” the darkness associated with the doom of the lost.
Biblical Usage
Ezekiel uses the adjective repeatedly for the temple’s outside court. In Matthew, “outer darkness” portrays the utter darkness of the judgment and exclusion awaiting the lost.
Historical Bible Dictionaries
International Standard Bible Encyclopedia (ISBE)
<p>out'-er: This adjective is used 12 times by Ezekiel of the outside court of the temple. In Matthew we find it 3 times (8:12; 22:13; 25:30) in "outer darkness" (to skotos to exoteron), which typifies the utter darkness of the doom of the lost.</p>