A measure of the inherent capacity for a
system, machine, or software to be modified,
re-engineered, or completely repurposed by the end-user. It is the antithesis of "proprietary" or "black-box" design.
In a
person, it refers to a high-level cognitive state characterized by a persistent "train of thought" dedicated to tinkering, troubleshooting, and seeking unconventional solutions—refusing to accept a design’s limitations as final.
I bought that old industrial CNC
mill specifically for its fuckwithity; within a week I had it
running custom
code to do things the manufacturer said were impossible.