You need to be more specific.
Obviate
OBVIATE, which means to make unnecessary.
unnecessary
a curse word or a violent or disgusting word such as sh*t crap turd BOB! That was an unnecessary word. Anything that has nothing to do with the subject in question is considered unnecessary.
The term for using unnecessary words is "verbosity." It refers to the excessive and often redundant use of words in speech or writing, which can make communication less clear and concise.
The anagram is the verb "obviate" (avoid or make unnecessary).
Actually, there is no one word that rhymes exactly with unnecessary.
unnecessary
The word "unnecessary" (not required) is spelled with two N's and two S's.
The unnecessary word in the phrase "Contains an unnecessary wordwhich one what sentences" is "which." The phrase is unclear and could be simplified for better understanding. A clearer version might be, "Identify the unnecessary word in the sentences."
"I find it unnecessary to ask such a simple question"
I think the word you might be asking of is "unnecessary".