1. What does it mean?
취준 shortens 취업 준비. It covers activities such as working on applications, preparing interviews, studying for recruitment tests, and exploring jobs. 취준생 is a person going through that process.
Also written or said as 취업준비, chwijun
2. The nuance
It is not limited to university students or first-time applicants. The label describes the activity, without specifying how long it lasts or why someone is currently between jobs.
3. Examples
“취준하면서 면접 연습 모임에 나가고 있어.”
While job hunting, I'm attending an interview-practice group.
“이번 주 취준 목표는 지원서 두 개 완성이야.”
My job-search goal this week is to finish two applications.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.