hold and state as one’s opinion.““The man is a genius,” he opined”
1.a passionate expression of grief or sorrow.
Lament is a statement of one’s opinion, but it is limited to grief or sorrow. You may also use it as “complaining”, as in the song I sang in high school choir, “Alto’s Lament”, which is a song about an alto who longs to sing melody for a change from harmony.
Opine, on the other hand, is an expression of any opinion. “This pizza is wonderful!” he opined. “Her skirt is too short,” she opined.
“We should use this word more often,” she opined.