WordNet
n. activity contributing directly to the output of an organization [syn: line function]
Usage examples of "line duty".
This released squadron after squadron for front-line duty in his next great onslaught.
For Warren, though he had never made any bones that he considered himself a superlative officer and a clever tactician, was not fond of the hazards of actual line duty.
I was told that was what you were, that you bitched unmercifully when the Marines pulled both of you off line duty and that you'd had serious experience in hot, hard, nasty flying conditions so you knew what you were going to be missing.
She had never seen line duty, but instead belonged to a general with a chronic ulcer who coveted her with the avidity of a religious zealot.
By making Dan Berrigan or Angela Davis the beneficiary you might avoid front-line duty.