Heresy

from a Greek word signifying (1) a choice, (2) the opinion
chosen, and (3) the sect holding the opinion. In the Acts of the
Apostles (5:17; 15:5; 24:5, 14; 26:5) it denotes a sect, without
reference to its character. Elsewhere, however, in the New
Testament it has a different meaning attached to it. Paul ranks
"heresies" with crimes and seditions (Gal. 5:20). This word also
denotes divisions or schisms in the church (1 Cor. 11:19). In
Titus 3:10 a "heretical person" is one who follows his own
self-willed "questions," and who is to be avoided. Heresies thus
came to signify self-chosen doctrines not emanating from God (2
Pet. 2:1).