close, v. — Green’s Dictionary of Slang

close v.

close down (v.)

(US Und.) to kill someone.

1985

T.R. Houser Central Sl. 15: close ’em down To kill someone or commit murder. To take someone out. ‘See that nigger; we gonna close ’em down.’.

close one’s face (v.)

close up (v.)

(Aus.) to stop talking.

1885		Bulletin (Sydney) 12 Sept. 11/3: He came on to the platform of St. George’s Hall, Geraldton, and told them that he would start by delineating Shakespeare’s birthplace. When they heard it wasn’t Geraldton, they asked Mr. James to ‘close up.’ He, after a bootless struggle, obeyed, and told them he would start into the sublime dramas.
1901		Queenslander (Brisbane) 31 Aug. 412/2: Weary Willie: Aw close up. I knowed Dusty Rhodes for five year .

close your head!

shut up! be quiet!

1894		‘Mark Twain’ Those Extraordinary Twins 🌐 ‘Shame! Such language! Can’t you understand? They were starving—actually starving—and he ate for both, and——’ ‘Shucks! you gimme a chance and I’ll—’ ‘There, now – close your head! and don’t you open it again till you’re asked.’.
1993		W. Denton Twists, Slugs and Roscoes 🌐 Why get in a car when you can hop in a boiler? Why tell someone to shut up when you can tell them to close their head? Why threaten to discharge a firearm when you can say, ‘Dust, pal, or I pump lead!’.

(US campus) be quiet!

1840		Ohio Democrat 7 Aug. 2/2: Mr Snapper, are you in favor iof Abolition? ‘Head in,’ cries his committee, ’close your shell and keep dark’.
1880		Concordia Eagle (Vidalia, LA) 8 Apr. 4/3: Never talk to people ona train [...] untl you have something to say, and then say it and close your shell.
1896		W.C. Gore Student Sl. in Cohen (1997) 10: close your shell Stop talking; hold your tongue.
1912		Lincoln County Leader 17 May 7/4: Don’t be a clam, my son, but if an old friend [...] asks for the loan of $5 until Saturday, just close your shell for repairs.