"Deficient in": This is the most common preposition to use when talking about a lack of something.
* Example: *The soil is deficient in nutrients.*
"Deficient of": This is also used to describe a lack of something, but it's less common than "deficient in."
* Example: *He was deficient of courage.*
"Deficient for": This preposition is used when something is not enough for a particular purpose.
* Example: *The funding is deficient for the project.*
"Deficient with": This preposition is used when someone is lacking in a particular skill or ability.
* Example: *She is deficient with numbers.*
Other prepositions: Depending on the context, you could also use other prepositions like "deficient on," "deficient from," "deficient against," etc.
Here are some examples of how these prepositions can be used in different contexts:
* Deficient in: The company is deficient in financial resources.
* Deficient of: The country is deficient of a strong leader.
* Deficient for: The plan is deficient for the long-term goals.
* Deficient with: He is deficient with his vocabulary.
Remember to choose the preposition that best conveys the meaning you want to express.