IPA: /ˌʌn.ləˈmɛn.tɪd/
KK: /ʌnˈlæmɛntɪd/
Not mourned or regretted after death or loss.
The unlamented passing of the old tree was hardly noticed by the neighborhood.
Unlamented → It is formed from "un-" (meaning not) and "lamented" (from Latin "lamentari", meaning to mourn or express sorrow). The word "unlamented" means not mourned or grieved for, indicating a lack of sorrow for someone or something that has passed.
Think of 'not' ('un-') mourning or expressing sorrow ('lamented') — that's why unlamented means not mourned.