To cause to feel uneasy, troubled, worried, guilty, or vexed; to bother about something.
To erode.
To consume or use up, erode or wear away gradually.
To annoy or irritate.
To stop.
To serve or behave as a spy or informer.
To complain.
To watch; to observe.
An unpleasant person, especially one who makes things difficult for others.
A police spy or informer.