A passive applicant is someone who is presently working and is not actively looking for a new job, but may be willing to consider new career prospects if approached by recruiters or employers. Unlike active applicants, who are actively searching for jobs and looking for new opportunities, passive candidates are often content with their existing position and do not actively seek a change. They may be willing to investigate new opportunities if offered with persuasive offers.
Example
A software developer at a computer business is approached by a recruiter from another company who promises a demanding career with more pay and more prospects for advancement. Although the developer is not actively seeking a new job, they are open to investigating the option owing to the good offer and the possibility of career progression.