mourn (v.) Look up mourn at Dictionary.com
Old English murnan "to mourn, bemoan, long after," also "be anxious about, be careful" (class III strong verb; past tense mearn, past participle murnen), from Proto-Germanic *murnan "to remember sorrowfully" (cognates: Old Saxon mornon, Old High German mornen, Gothic maurnan "to mourn," Old Norse morna "to pine away"), probably from PIE root *(s)mer- "to remember" (see memory); or, if the Old Norse sense is the base one, from *mer- "to die, wither." Related: Mourned; mourning.