Synonyms:
* Outside: This is the most straightforward synonym, directly indicating something located on the exterior.
* Exterior: Similar to "outside," emphasizing the outer surface or appearance.
* Outer: Another word for the external part or layer.
* Foreign: Refers to something originating from outside, often used in a political or cultural context.
* Extrinsic: Emphasizes the external origin or influence.
Antonyms:
* Internal: The direct opposite of external, referring to the inside or within something.
* Intrinsic: Emphasizes the internal origin or nature of something.
* Inner: Similar to "internal," focusing on the interior or innermost part.
* Inherent: Refers to something that is an essential and inseparable part of something, originating from within.
The best synonym or antonym for "external" will depend on the specific context of its use.