The key word is "involuntary." The person wants to work but is forced into unemployment by economic conditions, distinguishing it from "voluntary" unemployment where someone chooses not to work.
Involuntary unemployment occurs when a person is willing and able to work at the prevailing wage rate but cannot find a job. This type of unemployment arises from factors beyond the individual's control, such as a recession leading to a lack of aggregate demand (cyclical unemployment) or a mismatch of skills (structural unemployment).