General Antonyms:
* Scarcity: This is the most direct opposite, meaning a lack of something.
* Shortage: Similar to scarcity, this refers to a lack of a sufficient amount.
* Paucity: This implies a small or insufficient quantity, often suggesting a lack of quality as well.
* Deficiency: This refers to a lack of something that is necessary or desirable.
Antonyms in Specific Contexts:
* If "plethora" refers to an abundance of choices, an antonym could be limited options.
* If "plethora" refers to an overabundance of something unwanted, an antonym could be lack or absence.
Ultimately, the best antonym for "plethora" depends on the specific situation and the meaning you want to convey.