The answer to this question will reveal the single greatest identifier of the antichrist who is the lawless one spoken of in 2 Thessalonians 2:-7.
The opposite of love is selfishness:
So if there is any encouragement in Christ, any comfort from love, any participation in the Spirit, any affection and sympathy, 2 complete my joy by being of the same mind, having the same love, being in full accord and of one mind. 3 Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves. 4 Let each of you look not only to his own interests, but also to the interests of others. 5 Have this mind among yourselves, which is yours in Christ Jesus, 6 who, though he was in the form of God, did not count equality with God a thing to be grasped, 7 but emptied himself, by taking the form of a servant, being born in the likeness of men. 8 And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross. 9 Therefore God has highly exalted him and bestowed on him the name that is above every name, 10 so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, 11 and every tongue confess that Jesus Christ is Lord, to the glory of God the Father. (Php 2:1–11, ESV)
For this is the message that ye heard from the beginning, that we should love one another. Not as Cain, who was of that wicked one, and slew his brother. And wherefore slew he him? Because his own works were evil, and his brother's righteous. [1 John 3:13 KJV]
Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. [John 8:44 KJV]
The wicked one, 1 John 3:13, of whom was Cain, is here characterised by Cain's slaying of his brother.
And the devil (diabolos), John 8:44, is here characterised by, firstly, murder and, secondly, by lying (to Eve, as a means to the murder of humanity in the beginning).
I would say that the opposite of love is murder - the negation of another rather than love to that other. The emotion is hatred ; the activity is murder.
... he that hateth his brother is a murderer. [1 John 3:15 KJV]
John, here, equates the two. One might say hatred is the opposite of love, but then hatred is the same as murder. There is an equivalence between the two. They are interchangeable.
And this murderous hatred is what characterises the Wicked One who shall be manifest, on earth, in humanity, in the last times.
The murder upon which he will be intent is the murder not of humanity generally, for humanity is that which he indwells. It will be the murder of the saints, God's people, the true Church, on which he will be focused.
This is already evident in certain parts of the world, today.