This is the 3469th most frequent Russian word.
пропали
"Пропали" means "disappeared" or "went missing."
Here, 'пропали' is used to indicate that the flowers have ceased to exist in the field, implying their disappearance.
На этом поле все цветы пропали.
In this field, all flowers disappeared.
In this case, 'пропари' signifies that the glasses are missing and their location is unknown.
Мои очки пропали, и я не могу их найти.
My glasses are gone, and I cannot find them.
Here, 'пропали' conveys the sense of losing hope or confidence, metaphorically.