Direct Translation:
* Mpenzi wa siri: This literally translates to "secret lover" and is the most straightforward option.
More Descriptive:
* Mpenzi aliyefichwa: This translates to "hidden lover," which implies a more deliberate attempt to conceal the relationship.
* Mpenzi haramu: This translates to "forbidden lover" and implies a relationship that is considered morally wrong or taboo.
* Mpenzi wa siri: This translates to "secret lover" and implies a relationship that is kept hidden from others.
Idioms/Figurative Language:
* Mpenzi wa usiku: This translates to "nighttime lover" and implies a relationship that is only possible when it's dark.
* Mpenzi wa kivuli: This translates to "shadow lover" and implies a relationship that is hidden from the public eye.
Ultimately, the best way to say "secret lover" in Swahili depends on the specific situation and the message you want to convey.