unmarked
//ʌnˈmɑːkt//
Adjective
unmarkedCanonical form
1
Having no visible marks, signs, or distinguishing features.
The detective drove an unmarked car to avoid being noticed.
2
Not noticed or recorded; unobserved or unacknowledged.
Her hard work went unmarked by her colleagues.
3
(Linguistics) Denoting the basic or default form of a word or grammatical category, without any special inflection or modification.
In English, the singular form of a noun is considered unmarked, while the plural is marked.