Criticism is a word used in two senses. Originally, it meant "a scholarly analysis and balanced judgement". Later (mid-20th century) it came to mean "a hostile attack" pointing out the bad features of the topic.

1. Constructive criticism: criticism to evaluate and improve. This is when somebody points out aspects of something else that could be improved or made better. This is an important activity, especially when dealing with young people. Parents and teachers often use this kind of criticism. In adult life it is widely used in literature, the arts and science.
2. Negative or destructive criticism: criticism as an attack on a person or idea. Negative criticism is often interpreted as an attack against a person (ad hominem), and appears often in debates between political opponents.