Webster’s Revised Unabridged Dictionary · 1913
Assertor
As·sert′or (ăs·sẽrt′ẽr), n. [L., fr. asserere.] One who asserts or avers; one who maintains or vindicates a claim or a right; an affirmer, supporter, or vindicator; a defender; an asserter.
The assertors of liberty said not a word. Macaulay.
Faithful assertor of thy country's cause. Prior.