Origin:
The idiom comes from the Bible, specifically from the Book of Proverbs (25:15): "As vinegar to the teeth and smoke to the eyes, so is the sluggard to him who sends him, and gall and wormwood to the soul."
Gall refers to the bile produced by the liver, which is extremely bitter. Wormwood is a plant with a very bitter taste, used in traditional medicine.
Example:
* "The constant criticism from her colleagues was gall and wormwood to her."
* "The news of his betrayal was gall and wormwood, leaving him feeling betrayed and heartbroken."
Similar expressions:
* Bitter pill to swallow
* Salt in the wound
* A slap in the face
Usage:
The idiom "gall and wormwood" is used to express strong negative emotions and is usually used in situations where someone experiences a deep sense of bitterness or resentment.