Anything that is contrary to God-given instructions throughout the entire Bible is "antichrist," and not necessarily a particular individual.
2 John 1.7
[SUP]7 [/SUP]For many deceivers have gone out into the world, those who do not acknowledge Jesus Christ
as coming in the flesh. This is the deceiver and the antichrist.
2 JOhn 2.18-22
[SUP]18 [/SUP]Children, it is the last hour; and just as you heard that antichrist is coming, even now many antichrists have appeared; from this we know that it is the last hour. [SUP]19 [/SUP]They went out from us, but they were not
really of us; for if they had been of us, they would have remained with us; but
they went out, so that [SUP][
d][/SUP]it would be shown that they all are not of us. [SUP]20 [/SUP][SUP][
e][/SUP]But you have an anointing from the Holy One, and you all know. [SUP]21 [/SUP]I have not written to you because you do not know the truth, but because you do know it, and [SUP][
f][/SUP]because no lie is of the truth. [SUP]22 [/SUP]Who is the liar but the one who denies that Jesus is the [SUP][
g][/SUP]Christ? This is the antichrist, the one who denies the Father and the Son.
1 John 4.1-3:
4 Beloved, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world. [SUP]2 [/SUP]By this you know the Spirit of God: every spirit that confesses that Jesus Christ has come in the flesh is from God; [SUP]3 [/SUP]and every spirit that does not confess Jesus is not from God; this is the
spirit of the antichrist, of which you have heard that it is coming, and now it is already in the world.
John clearly tells us antichrist can be a spirit and/or an individual, not just an thought or idea. It is also not "contrary to God-given instructions throughout the entire Bible" It is clearly defined as a spirit or person which states Jesus did not come in the flesh.
Furthermore, discerning of spirits is a gift found in 1 Cor 12 and is not something every believer has or will be given, it is a gift given as the Spirit wills. This gift allow you to see and hear into the spiritual realm.
Every Believer is given spiritual discernment, but not discerning of spirits.