a sharp projection on an object such as a hook or arrow that is angled away from the main point, so that once impaled on the object, it is difficult to remove oneself;
e.g. The arrowhead had a barb so that it causes more injury if the victim tries to remove it.
(noun)
a sharp remark that is intended to be deliberately critical or hurtful;
e.g. She aimed another barb at him, this time insulting his selfishness.
(noun)
a cluster of sharp projections or spikes on a wire fence;