1.
new member of the workforce; person who just started working
A person who has recently graduated from school and entered the workforce for the first time. In Japan, this typically refers to the cohort of graduates who start their jobs in April.
Cultural note
新社会人 reflects Japan's synchronized hiring system, where most companies hire fresh graduates (新卒) and start them on April 1st. The spring season features many advertisements and products marketed to 新社会人, from suits and business bags to self-help books.
Etymology
新 (new) + 社会人 (member of society / working adult). The term 社会人 itself distinguishes working adults from students.