Green’s Dictionary of Slang

arsey-varsey phr.

also arce-versa, arsey-versey, arsie-versie, arsy-versy, assy-turvy
[arse n. (1) + sfx -y + redup.; on model of SE vice-versa; prior use before mid-16C was SE]

1. [mid-16C+] upside down, topsy-turvy, back-to-front.

2. [late 16C+] head-over-heels; usu. in phr. fall arsey-varsey, fall head-over-heels.

3. [mid-17C–early 18C] contrary, perverse, preposterous.