"He used an adjective"

A profanity in Dickens.

Charles Dickens, Barnaby Rudge (1841), chapter 31. Joe Willetts has run away to join the army. As luck would have it he meets a recruiting serjeant at an inn.
"You're a gentleman, by G—!" was his first remark, as he slapped him on the back. "You're a gentleman in disguise. So am I. Let's swear a friendship."
Joe didn't exactly do that, but he shook hands with him, and thanked him for his good opinion.
"You want to serve," said his new friend. "You shall. You were made for it. You're one of us by nature. What'll you take to drink?"
"Nothing just now," replied Joe, smiling faintly. "I haven't quite made up my mind."
"A mettlesome fellow like you, and not made up his mind!" cried the serjeant. "Here—let me give the bell a pull, and you'll make up your mind in half a minute, I know."
"You're right so far"—answered Joe, "for if you pull the bell here, where I'm known, there'll be an end of my soldiering inclinations in no time. Look in my face. You see me, do you?"
"I do," replied the serjeant with an oath, "and a finer young fellow or one better qualified to serve his king and country, I never set my—" he used an adjective in this place—"eyes on."
"Thank you," said Joe, "I didn't ask you for want of a compliment, but thank you all the same. Do I look like a sneaking fellow or a liar?"
The serjeant rejoined with many choice asseverations that he didn't; and that if his (the serjeant's) own father were to say he did, he would run the old gentleman through the body cheerfully, and consider it a meritorious action.