I love this cool article on Lawyerist in which the author analyzes Justice Scalia's use of the word "argle-bargle" in his dissent in United States v. Windsor (the DOMA case). The author also outlines other fun words that have appeared in opinions, including "jibber-jabber," "gobbledygook," and--my favorite--"higgledy-piggledy."
I did a little research of my own and found some more interesting word pairs, including:
-fuddy duddy (Butler Lime and Cement Co. v. Occupational Health and Safety Comm'n, 658 F.2d 544, 548 (9th Cir. 1981));
-dilly dally (Kam Hon, Inc. v. Cigna Fire Underwriters Ins., 933 F. Supp. 1060, 1063 (M.D. Fla. 1996)); and
-hocus pocus (Tucker v. Sebelius, No. 07-2230 (RBK), 2010 WL 2761525, at *2 (D.N.J. July 12, 2010)