What is voluntary unemployment and what keeps people as voluntary unemployed?

Voluntary unemployment refers to a situation where a person who is able to work remains unemployed due to his/her own willingness. Under this situation, the person remains unemployed despite jobs being available in the market. Various factors can be responsible for a person to remain unemployed voluntarily. Some of the reasons can be waiting for a job suitable to a person's qualifications, inappropriate salary, lack of mobility, etc.