"Compliance" is the inverse of stiffness, it just means that your machine is flexible. The idea is very simple, but the unfolding of it (no pun intended) is pretty awesome.

https://en.wikipedia.org/wiki/Compliant_mechanism

#CompliantMechanism

Compliant mechanism - Wikipedia

This looks like a good, short video with examples of compliant mechanisms.

https://www.youtube.com/watch?v=C-SbMsYNTxM

COMPLIANT MECHANISMS COMPILATION - make the World flexible

YouTube