Boyd’s Bible Dictionary:
(swearers out). Those who pretended to drive out evil spirits by prayers and conjurations (Matt. 12:27; Mark 9:38; Acts 19:13).
Concise Bible Dictionary:
The incident recorded in Acts 19:13-16, raises the question as to what was an “exorcist”? The disciples of the Lord who were able to cast out demons were never so called. Were these vagabond or wandering Jews able to cast out demons irrespective of the name of the Lord Jesus? or did they only pretend to do so? Matthew 12:27 is often quoted to show that the Lord admitted that such persons were able to cast out demons. Is it not more probable that the Lord was in that passage alluding to His disciples? The Lord was a mysterious person whom they could not comprehend; and He was charged with casting out demons by the prince of demons; but the Lord said, By whom do your children (the origin of whom you do know) cast them out? On the other hand, the Lord describes some of the lost as pleading that they had cast out demons in His name (Matt. 7:22); but these also speak of having prophesied in His name; so that they would be persons who had made a profession, as Judas who was sent out with the other apostles.
On one occasion the disciples met with a man who was casting out demons in the name of the Lord, whom they forbad because he followed not with them; but the Lord said that no one who did a miracle in His name could lightly speak evil of Him (Mark 9:38; Luke 9:49). On the whole it seems plain from scripture that the casting out demons could only be by the power of God. As explained by the Lord, Satan would not destroy his own kingdom. What power the exorcists really had we know not, but in the case under consideration God did not allow them to use the name of the Lord Jesus, and the demon overpowered and wounded them.
Strong’s Dictionary of Greek Words:
Transliteration:
exorkistes
Meaning:
from 1844; one that binds by an oath (or spell), i.e. (by implication) an "exorcist" (conjurer)