General Opposites:
* Absence: This is the most straightforward opposite, meaning "not being present."
* Nonexistence: This emphasizes the lack of being or existence at all.
* Void: This emphasizes the emptiness or lack of something where something should be.
Specific Opposites depending on context:
* Neglect: If you're talking about someone's presence in someone else's life.
* Exclusion: If you're talking about being included or excluded from a group or situation.
* Silence: If you're talking about the presence of a sound or noise.
* Darkness: If you're talking about the presence of light.
To determine the best opposite word, consider the specific situation where you want to use it.