Humans are social being and we cannot live alone. We have to interact with our environment and communicate with the society to live a fulfilling life.
Stigma is a set of negative and unfair Beliefs and judgement that prevails in every society. For example 'stigma of illnesses', 'stigma of poverty' etc.
Stigma hinders the growth and development of an individual both physically as well as mentally. For instance Fear of stigma makes an individual introvert as they usually try to avoid crowds and social gathering for fear of being judged. This makes an individual dull and less active being stuck in the four corners of his/her house.
Sigma Often leads to discrimination which may be direct Such as Giving bad and negative feedback about a person background, illness etc. Or it may be indirect such as avoiding a person because of their illness with the fear that it is infectious. For example people in some society usually tends to avoid family of sucides (people who commit sucides) because of the believe that sucide is hereditary and can influence other people around them as well.
Stigma are usually irrational and baseless beliefs and judgements. A good society should try to be free from "stigma" to make a suitable environment for the growth and development of every members in the society.