dipsy-doodle, n. — Green’s Dictionary of Slang

dipsy-doodle n.

[baseball jargon dipsy-do, a deceptive sinking curveball, associated with pitcher Carl Hubbell; ult. SE dip; 1937 may refer to a dance popularized that year]

1. (US) trickery, scheming.

1937		Tommy Dorsey 🎵 You can’t eat, you can’t sleep. You go crazy. / You’re just a victim of the dipsy doodle.
1942		R. Chandler High Window 177: I opened the front door, leaving the key in the lock. I wasn’t going to work any dipsy-doodle in this place. Whatever was, was.

2. (US) a person-to-person insult.

1938

Oakland Trib. (CA) 9 Jan. 10/1: Mr Russ Whiting [...] pens an open letter to ‘Art Cohen, the Oakland dipsy-doodle’.