Definition of On the job

• relating to or associated with a job or employment; "on-the-job training"; "on-the-job requirements"
• actively engaged in paid work; "the working population"; "the ratio of working men to unemployed"; "a working mother"; "robots can be on the job day and night"
• watchful and prepared for action; "bird watchers on the alert for a rare species"; "cops were on the job and caught them red-handed"