rancid

adj

1. smelling of fermentation or staleness

Synonym: sour

2. (used of decomposing oils or fats) having a rank smell or taste usually due to a chemical change or decomposition

e.g. rancid butter
rancid bacon

1. （脂肪食物）变坏的，发臭的
If butter, bacon, or other oily foods are rancid, they have gone bad and taste old and unpleasant.

e.g. Butter is perishable and can go rancid.
黄油很容易变质，而且会发臭。
e.g. ...the odour of rancid milk.
腐败牛奶发出的臭味

1.

1. 腐臭的：8. crusty 像壳一样硬的 | 9. rancid 腐臭的 | 10. stagnant 污浊的