noun
fasting; abstaining from food and drink
Formal or technical term for complete abstention from eating and drinking, often used in medical, religious, or procedural contexts.
手術の前は絶飲食を指示された。
I was instructed to fast before the surgery.
この検査では12時間の絶飲食が必要です。
This test requires 12 hours of fasting.
絶食 refers specifically to abstaining from food, whereas 絶飲食 includes abstaining from drink as well.
Compound of 絶 (ぜつ, 'to cut off') + 飲食 (いんしょく, 'eating and drinking'). The reading ぜついんしょく follows standard on'yomi patterns.