Inessential (adjective)
Not essential.
“Leave inessential items behind when there is a fire alarm.”
Inessential (adjective)
Lacking essence or being.
Inessential (noun)
Something that is not essential
Unessential (adjective)
Not essential.
“inessential|unimportant”
“essential”
Unessential (adjective)
Void of essence, or real being.
“unsubstantial”
Wiktionary