Like many political and medical terms, this word has a Latin origin and consists of two parts. The prefix dis carries a denying meaning, and the root sident means consent. So, a dissident is by definition a dissenting person.
The only question is what he is actively opposing. In Soviet times, this proud tribe was often referred to by people who listened to Voice of America and expressed their protest in the kitchens of small-sized Khrushchevs while drinking port 777 for squash caviar and sprats in tomato.
It was believed that the ears of the omnipotent KGB were eavesdropping on such “intelligent people” and, to protect themselves from them, they turned on the radio or opened water taps. To add romanticism, friends were inspired by the idea that the dissident is a desperate person, internally free and not afraid of any satraps there.
As it turned out now, they tried in vain. If information about such sedition reached the employees of the first department, then, as a rule, it came from someone present (sometimes it was he who opened the valve). Moreover, such information in the era of the late Brezhnev socialism did not entail conclusions in the terrible basements of the Lubyanka, so they would scold everyone ...
A true dissident is a citizen who has clearly defined ideological contradictions with the dominant ideology and does not hide his convictions, no matter what the cost. This is his distinction with kitchen conspirators, whose expression of dissatisfaction was limited to showing a cookie in his own pocket.
The fate of many Soviet writers who began their careers with writing works published in the USSR is interesting. Usually they didn’t at all plan to write specifically something against the authorities, they simply set out stories from their lives (sometimes enriched by camp experience). Dissident writers such as Alexander Solzhenitsyn or Varlam Shalamov gained fame thanks to Soviet publications, they simply gave many people the opportunity to learn the truth about the lives of millions of prisoners. And the conclusions and generalizations arose in the minds themselves ... At the same time, expulsion from the country became a real tragedy for them, although ahead was pretty materially secure life in the West, and even sometimes the Nobel Prize.

The fight against this phenomenon has been given really considerable attention. A huge explanatory work was carried out among the population, the meaning of which was to assert that the dissident is either an ideological saboteur bought with Western money or a madman.
The last statement was supported by numerous examples of inappropriate behavior of some opponents of the Soviet regime. Vladimir Bukovsky, who had been exposed to correctional psychiatry for a long time, admitted in a recent interview that many Soviet dissidents were indeed sick people. Normal citizens lived an ordinary life, went to work, celebrated Soviet holidays, studied, being interested in the situation in the world and the internal situation only within the framework of production political information. Self-immolations on Red Square were the destiny of few protesters against the entry of troops into Czechoslovakia or Afghanistan.
Most often it happened that the dissident became the one who sincerely believed in the just structure of socialist society, and did not agree only with individual, as it seemed to him, distortions of the communist idea, not suspecting that he had touched some of the cornerstones of this system. The fate of such a naive romance became unenviable.