A straightforward noun for someone without a job. Often used in formal or statistical contexts, but also in everyday speech.
He is currently unemployed, but he intends to find a job soon.
The proportion of unemployed people is increasing.
無職 is a noun or no-adjective meaning 'unemployed' or 'without occupation'. 無職者 adds the person suffix 者, explicitly referring to the person.
Compound of 無 (mu, 'without') + 職 (shoku, 'job') + 者 (sha, 'person').