underworking

To require too little work from; to work insufficiently.

To work or operate in secret or clandestinely.

To do less work than necessary (on).

“to underwork a painting”

To do work for inadequate payment.

To injure by working secretly; to destroy or overthrow by clandestine measure; to undermine.

To do similar work for a lesser price than; to undercut.

“One mason may underwork another.”

Lower or underlying workings