"discontinued practice" is correct and usable in written English.
You can use it when discussing a practice or activity that has been stopped or is no longer happening. For example: "The discontinued practice of offering free refills quickly led to a decrease in revenue for the restaurant."
Farmers in semi-arid areas of Lebanon should discontinue practicing barley monoculture and adopt a barley legume, such as common vetch, rotation.
But emails between Unaoil and Halliburton/KBR employees during the Justice Department's investigation into previous bribery allegations show a company rushing to discontinue practices that could raise red flags with investigators, but not severing the underlying partnership.
Among the barriers to improving delivery of effective interventions to prevent preterm birth and stillbirth is how to discontinue practices and interventions that have been shown to be ineffective or harmful.
So, sometime during the last few decades, these museums discontinued the practice or forgot about it.
Others have discontinued the practice as being inhumane or too costly for appropriate care.
After the Japanese crackdown, however, the Philippine government discontinued the practice.
The more reputable internet service providers have discontinued the practice of sending "non-delivery reports".
At United Fruit, he discontinued the practice of shipping bananas on the stem, which resulted in heavy losses from bruising.
Fewer Mexicans appear to be wearing masks, and restaurants that put large containers of hand-sanitizing gel at their entrances have discontinued the practice.
This epidemic of A.D.H.D. arguably began soon after American parents discontinued the practice of administering the dreaded daily spoonful of cod-liver oil!
