A backward regression; a reverting back to a worse state.

A dance move in which the feet are alternately slid back and the heels lifted, giving the illusion of walking forwards while actually moving backwards; later popularly called the moonwalk.

To regress; to slip backwards or revert to a previous, worse state.

“He felt better for a little while, before his condition started to backslide.”

To shirk responsibility; to renege on one's obligations or commitments.

“Rich countries are backsliding on their commitment to agree to new WTO measures to help people in poor countries gain access to affordable medicines. — Oxfam press release, 24 June 2002”