mournful; expressing sadness
Suddenly he heard a plaintive melody on the flute, but he couldn't tell where it was coming from.
plangere (to lament) (Latin)
lol its so easy wtf plaintive = remove L pain + tive = mournful Plaintive can be split into plain (plane)+tive (relative). Suppose a relative dies in a plane crash, we mourn. Thus plaintive = mourn. Sorry for the sadistic mnemonic.