Allah will throw back their mockery on them and leave them alone in their trespasses; so they wander to and fro like blind.
Meaning:-
Mockery: insulting, making a fool out of someone, To make fun of, teasing and contemptuous language.
trespasses: sin, error, wrongdoing, misdeed.
Wander: walk or move in a leisurely, casual, or aimless way.