Easton's Bible Dictionary (1897)
That faculty of the mind, or inborn sense of right and wrong, by which we judge of the moral character of human conduct. It is common to all men. Like all our other faculties, it has been perverted by the Fall (John 16:2; Acts 26:9; Rom. 2:15). It is spoken of as “defiled” (Titus 1:15), and “seared” (1 Tim. 4:2). A “conscience void of offence” is to be sought and cultivated (Acts 24:16; Rom. 9:1; 2 Cor. 1:12; 1 Tim. 1:5, 19; 1 Pet. 3:21).
Hastings' Dictionary of the Bible (1898)
CON'SCIENCE is the inborn sense of right and wrong, the moral law written on our hearts which judges of the moral character of our motives and actions, and approves or censures, condemns or justifies us accordingly. Rom 2:15. This universal tribunal is established in the breast of every man, even the heathen. It may be weakened, perverted, stupefied, defiled, and hardened in various ways, and its decisions are more or less clear, just, and imperative according to the degree of moral culture, John 8:9; Acts 23:1; 2 Chr 24:16; Rom 9:1; and 1 Tim 1:5.