The preposition "against" typically follows the verb "defend." For example, "She defended herself against the accusations."
Socrates is questioning the validity of Meletus's accusations by refuting his claims and pointing out inconsistencies in his arguments. He is trying to expose the weaknesses in Meletus's case in order to defend himself and show that the accusations are unfounded.
Darcy gave Elizabeth a letter the morning after he had proposed, and she refused, at Hunsford, in Kent. The purpose of the letter was to defend himself from the accusations she had made against him as she rejected him.
He made his famous Checkers speech to defend himself against accusations that he improperly used campaign contributions for personal expenses.
She had to defend herself from the false accusations made against her.
Desdemona was captivated by Othello's accounts of military adventures and exploits, so he defends himself. Desdemona appears and verifies her real love for the Moor as he explains that her love for him is not based on witchcraft.
Defendant.
I have never heard of accusations by the Church of Christ against the Catholic Church. The Catholic Church is a world-wide federation of particular Churches each headed by a Bishop. To the best of my knowledge the Catholic Press has not addressed any such accusations, nor has the Vatican.
Bring attention to these false accusations, keep digging into them and eventually the judge will see there is no substance to them. The narcissist will be descredited.
The soldier had to defend the fort from enemy attack.
The Irishman used a shillelagh to defend himself against the thugs.
In his letter to Elizabeth, Darcy addresses the accusations of him being arrogant, prideful, and responsible for Bingley's separation from Jane. He explains that his reserved nature may have been misunderstood, admits his past mistakes, and provides evidence to disprove the accusations against him, particularly in regard to Bingley and Jane's situation. Darcy also expresses his genuine feelings for Elizabeth and hopes for her forgiveness.