Failure to speak out can be described as SILENCE. SILENCE is the lack of sound or verbal communication. It is a form of non-verbal communication that can be used to convey a variety of emotions, such as fear, sadness, or even agreement. SILENCE can also be used to express disapproval or disagreement. In some cases, SILENCE can be seen as a sign of respect or understanding. SILENCE can also be used to create an atmosphere of contemplation or reflection.