coil, roll, bundle, tie up
綑 centers on wrapping or fastening something into a compact unit: coiling, rolling, bundling, or tying up.
綑 combines 糸 (thread) with 困, which likely contributes the sound and the idea of enclosing or bundling. The exact historical development of 困 within this character is uncertain.
Thread 糸 wraps around something enclosed 困, like coiling a rope around a bundle to tie it up.
For コン, imagine a con artist tying up a bundle of fake goods with thread: con -> コン, and the thread coils around the bundle.