on the job

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”

relating to or associated with a job or employment

• “on-the-job training”
• “on-the-job requirements”

watchful and prepared for action

• “bird watchers on the alert for a rare species”
• “cops were on the job and caught them red-handed”