Lead is unquestionably heavier than an equal volume of feathers.
She was unquestionably the victor.
Seeing as unquestionably starts with a vowel, U, you should use 'an' before it.
This word is an adverb.
Unquestionably Mrs. Jarley had an inventive genius.
If you mean by word "unquestionably".
You can use the word Truss in a sentence like this.
Can you use the word concluding in a sentence? Done.
Just use it! Or do you mean, can you use the word beheld in a sentence.
How do you use the word decibel in a sentence?What is decibel used for?
You can use the word Terrorist in a sentence as " Muslims are not terrorist ".
You just did use the word colonize in a sentence.
Since that is not a word I would not attempt to use it in a sentence.