General antonyms:
* Unimportant: This is the most direct opposite.
* Trivial: This emphasizes the lack of significance.
* Insignificant: Similar to "trivial," but often implies a smaller scale.
* Minor: Refers to something of lesser weight or consequence.
* Negligible: Means something so small or insignificant that it can be ignored.
* Irrelevant: Meaning something that is not related to the topic at hand.
Antonyms depending on the context:
* Unnecessary: If something is unimportant, it might be unnecessary.
* Superficial: This implies a lack of depth or substance.
* Frivolous: Describes something that is light-hearted and lacking seriousness.
* Meaningless: Describes something without any purpose or value.
The best antonym for "important" depends on the specific context and the nuance you want to express.