[W]ith a purple choking face, [Mr. Osborne] then began. "How dare you, sir, mention that person's name before Miss Swartz to-day, in my drawing-room? I ask you, sir, how dare you do it?"
"Stop, sir," says George, "don't say dare, sir. Dare isn't a word to be used to a Captain in the British Army."
"I shall say what I like to my son, sir. I can cut him off with a shilling if I like. I can make him a beggar if I like. I WILL say what I like," the elder said.
"I'm a gentleman though I AM your son, sir," George answered haughtily. "Any communications which you have to make to me, or any orders which you may please to give, I beg may be couched in that kind of language which I am accustomed to hear."
Whenever the lad assumed his haughty manner, it always created either great awe or great irritation in the parent. Old Osborne stood in secret terror of his son as a better gentleman than himself; and perhaps my readers may have remarked in their experience of this Vanity Fair of ours, that there is no character which a low-minded man so much mistrusts as that of a gentleman. (21.35-39)
Osborne has worked all his life to make a gentleman of his son, but when George actually starts acting like one, he doesn't like what he sees. George takes on not just the outward qualities of a gentleman – good looks, good manners, and money – he also sometimes busts out the whole "honor" thing. This is extremely threatening to Osborne, most likely because honor and smart business practices don't really mix. When George talks about his gentlemanly honor, Osborne feels his son is overstepping him socially and cannot help but be envious of his creation.