What word does Mark Antony keep repeating

I assume this question is referring to Mark Antony's famous funeral oration for Julius Caesar. When Antony arrives at the Forum and sees Caesar's slain body, Brutus pleads with him not to sound the alarm, lest the conspirators have to kill Antony, too. He explains that they murdered Caesar for the good of Rome, and that while the deed looks dreadful, the intent behind it was pure:

Though now we must appear bloody and cruel,As, by our hands and this our present act,You see we do, yet see you but our handsAnd this the bleeding business they have done:Our hearts you see not; they are pitiful;And pity to the general wrong of Rome—[...]Only be patient till we have appeasedThe multitude, beside themselves with fear,And then we will deliver you the cause,Why I, that did love Caesar when I struck him,Have thus proceeded.

Antony, not wanting to die, pretends to agree with Brutus that there must have been some noble motivation for this crime, saying "I doubt not of your wisdom." He shakes hands with each of the conspirators, deliberately smearing himself with Caesar's blood—making himself look complicit in the murder—to earn their trust. He insists:

Friends am I with you all and love you all,Upon this hope, that you shall give me reasonsWhy and wherein Caesar was dangerous.

Brutus agrees that Antony, as a dear friend of Caesar's, deserves to "be satisfied" with a full statement of the conspirators' reasons for the murder. Antony says, "That's all I seek," and asks one more favor: to be allowed to speak as a friend at Caesar's funeral. Brutus allows this, despite the misgivings of the other conspirators, because Brutus is certain that Antony will be convinced by their logic in killing Caesar and will agree that the crime was done for the general good of Rome.
Brutus presents his case to the people of Rome at Caesar's funeral, where he is the first to speak, saying:

If then that friend demandwhy Brutus rose against Caesar, this is my answer:—Not that I loved Caesar less, but that I lovedRome more. Had you rather Caesar were living anddie all slaves, than that Caesar were dead, to liveall free men? As Caesar loved me, I weep for him;as he was fortunate, I rejoice at it; as he wasvaliant, I honour him: but, as he was ambitious, Islew him.

The crowd (who are easily swayed) are moved by Brutus's speech and cheer for him, some even declaring "This Caesar was a tyrant" and calling for a statue of Brutus to be erected in his honor.
Antony's speech follows Brutus's, and at first, Antony seems to agree with Brutus's reasoning:

The noble BrutusHath told you Caesar was ambitious:If it were so, it was a grievous fault,And grievously hath Caesar answer'd it.

However, Antony begins to turn the mood of the crowd by the repeated use of the words "noble," "honourable," and "ambitious." He hammers these words, gently at first and then with increasing force, throughout his speech like nails. The conspirators are "noble" and "honourable," and Caesar was "ambitious"—or is it the other way around? After all,

[Caesar] hath brought many captives home to RomeWhose ransoms did the general coffers fill:Did this in Caesar seem ambitious?When that the poor have cried, Caesar hath wept:Ambition should be made of sterner stuff

But despite the good that Caesar did for Rome,

Brutus says he was ambitious;And, sure, he is an honourable man.

Antony insists that he speaks "not to disprove what Brutus spoke," but his speech is crafted to do just that. The refrain that Brutus "is an honourable man" seems sincere at the outset but becomes increasingly sardonic, until Antony's true feelings—his rage at Caesar's murder—burst through. And yet even this outburst is calculated to inflame the mood of the crowd, and to underscore that what the conspirators did was in no way honourable:

O masters, if I were disposed to stirYour hearts and minds to mutiny and rage,I should do Brutus wrong, and Cassius wrong,Who, you all know, are honourable men:I will not do them wrong [...]Good friends, sweet friends, let me not stir you upTo such a sudden flood of mutiny.They that have done this deed are honourable:What private griefs they have, alas, I know not,That made them do it: they are wise and honourable,And will, no doubt, with reasons answer you.

Though Antony, with false modesty, claims to be "no orator," he has successfully whipped up the fury of the Romans against the conspirators. While only minutes before, the crowd was ready to raise a statue to Brutus, they are now determined to kill him for murdering Caesar.