|Noah Webster's Dictionary|
1. (n.) One who believes some doctrine contrary to the established standards or prevailing religion.
2. (n.) One who having made a profession of Christian belief, deliberately and pertinaciously refuses to believe one or more of the articles of faith determined by the authority of the universal church.
Int. Standard Bible Encyclopedia
her'-e-tik, her'-e-tik, he-ret'-i-kal (hairetikos): Used in Titus 3:10, must be interpreted according to the sense in which Paul employs the word "heresy" (1 Corinthians 11:19 Galatians 5:20) for "parties" or "factions." According to this, the Scriptural meaning of the word is no more than "a factious man" (American Standard Revised Version), an agitator who creates divisions and makes parties. Weizsacker translates it into German ein Sektierer, "a sectarist." The nature of the offense is described in other words in 2 Thessalonians 2:6, 11.
Heretic (1 Occurrence)
Titus 3:10 A man that is an heretick after the first and second admonition reject; (Root in KJV DBY WBS)