Green’s Dictionary of Slang

1. (US) to explain.

1907

W.M. Raine Bucky O’Connor (1910) 21: I merely wanted to frame up to you how this thing’s going to turn out.

2. to form a plan of action, esp. in secret.

1900		Ade More Fables in Sl. (1960) 107: Other Delsarte such as the Respected Farmer usually Frames Up for his Wife.
1905		H. Green Actors’ Boarding House (1906) 77: Ain’t no way we kin frame this thing up.
1914		S. Lewis Our Mr Wrenn (1936) 181: There’s going to be a vacant room there – maybe you two fellows could frame it up to take it.
1925		Dos Passos Manhattan Transfer 114: How’d ye like it if I went an told her how you an me framed it up to stand [...] huggin and kissin just to make her fall for yez.
1931		O. Strange Law O’ The Lariat 159: I dunno just how they got it framed up [...] but they got me to reckon with yet.
1980		J.L. Gwaltney Drylongso 225: These doctors was framin’ up on gettin’ several armfuls of law when my girl walked in.

3. to link together, e.g. of a couple.

1913

J. London Valley of the Moon (1914) 17: Nothin’ doin’, Bo, [...] Me an’ Saxon’s framed up to last the day.

4. see frame v. (6)