kon'-ker-er: Known only in the compound verb (hupernikomen, Ro 8:37): A usual meaning of the preposition in composition is "above all measure"; hence, "more than conquerors," the Revised Version (British and American), the King James Version. The comparison is to the completeness of the victory. Others may place their enemies in subjection; those here mentioned master not only their foes, but themselves. Others destroy their foes and their resources; while those who are "more than conquerors" convert foes into means of still farther promoting the interests for which they struggle (Ro 3:3-5). Nor is the victory external and transient, but internal and permanent.
⇒See the definition of conqueror in the KJV Dictionary
H. E. Jacobs