Here are some synonyms for inconsequential:
* Unimportant
* Trivial
* Minor
* Negligible
* Insignificant
* Meaningless
* Worthless
Examples:
* "The broken button was an inconsequential detail."
* "Their argument was inconsequential to the overall outcome."
* "He made an inconsequential error on the test."
In contrast to:
* Consequential means having significant importance or consequence.
* Significant means important or noteworthy.
* Major means large or important.