unback means to remove the back or backing from (something). Lexicurio rates it Sui generis — a strength score of 85 out of 100.
Etymology
From un- + back.
verb
- To remove the back or backing from (something).““When you go home,” resumed Josephine, “unback the miniature case and upon the surface opposite the painting you will find these words […]””
- To deprive (a horse) of its rider.“Her horse againe this Princesse must vnbacke,”