The crossword solution for the term 'BACK UP ON A JOB' is ABET, which is a four-letter word. ABET is a verb meaning to actively encourage or assist someone in doing something, especially something wrong or illegal. It can also mean to support or approve of something. In this context, it could mean to provide assistance to someone who is struggling with a JOB, or to provide moral support to someone who is trying to do a good JOB.