Non-specific

In English, the words a or an are indefinite articles that are used to refer to a person or thing that is non-specific, such as something generic or something mentioned for the first time.

Source: tatoeba (8424002)

The symptoms of malaria, which strikes an estimated 200 million people around the globe every year, are non-specific. That means the fever, aches, pains and chills in the early stages could be mistaken for any number of infections.

Source: tatoeba (12252390)

Ventnor: […] Failure in 2021 to attract Government interest as part of the Restoring your Railways scheme was blamed on it being too non-specific.

Source: wiktionary