One good descriptive adjective for Mark Antony would be "loyal." He was steadfastly loyal to Julius Caesar while Caesar was alive, and he used his wits and oratorical skill to render what service he could to Caesar after his friend had been assassinated. Since Caesar had appointed Octavius his heir in his will, Antony was primarily responsible for Octavius gaining the political and military power that had previously belonged to Caesar. So Antony transferred his loyalty from Caesar to Octavius, rather than attempting to assume Caesar's power in Rome for himself, as he could easily have done.
Another good adjective adjective would be "pragmatic." Antony uses the mob to overthrow the conspirators and then thinks about how he can cut them out of some of the benefits of Caesar's will. He pretends to accept Lepidus as part of the triumvirate but tells Octavius they should not really consider him an equal partner. In Shakespeare's Antony and Cleopatra, Antony apparently has Lepidus carried off and murdered.
Another adjective would be "resourceful," for reasons similar to those mentioned in the paragraph above. Antony is in a perilous situation when Caesar is murdered, yet he manages to turn the people against the conspirators and then defeat Cassius and Brutus in war. There are some remarkable characters depicted in Shakespeare's play, and Antony is certainly one of them.
Another adjective would be "courageous." Antony is a seasoned warrior. He has a reputation for being, as Cassius calls him, "a masker and a reveller," but when there is fighting to be done he is a formidable warrior and general. Prior to the Battle of Philippi, he displays his coolness, his leadership qualities, and his strategic wisdom. He obviously learned a lot about warfare and leadership from the great Julius Caesar.
An adjective that would have to be added is "hedonistic." It is well known to everybody that Antony loves luxuries and dissipation. Cassius calls him "a masker and a reveller," and Julius Caesar teases him about his weakness for pleasure. When Antony comes to join the others in escorting Caesar to the Capitol in Act II.2, Caesar says affectionately:
See, Antony, that revels long nights
Is notwithstanding up. Good morrow, Antony.
Antony's weakness for wine, women and song will prove to be his undoing in Shakespeare's Antony and Cleopatra, as it did in real history. Antony neglects his responsibilities as ruler of half the Roman world and allows Cleopatra to lead him in a life of debauchery. His moral degeneration leads to his loss of friendship with Octavius and then to the loss of respect from many of his oldest and most loyal followers. When Octavius goes to war against him, Antony is easily defeated. He and Cleopatra both commit suicide.