All 5 Uses

lament
in
Medea, by Euripides (translated by: G. Theodoridis)
(Auto-generated)

Can you not hear the wailing of this lamentable maiden?†

lamentable = regrettable

standard suffix: The suffix "-able" means able to be. This is the same pattern you see in words like breakable, understandable, and comfortable.
Chorus: I've heard the scream of bitter pain, the scream of lamentation.†
*

lamentation = passionate expression of grief or sorrow
It is no surprise to us that you lament your fate...Enter Creon with attendants.†

lament = express grief or regret
The old woman stopped her prayers and began a sad lament, a dirge full of tears and she began tearing at her grey hair.†
Grief and lamentation.†

lamentation = passionate expression of grief or sorrow

Definitions:

(1) (lament)
to express grief or regret
(2) (meaning too rare to warrant focus)
Although lament typically refers to a feeling or simple vocal expression, it can refer to a vocal expression as complex as a sad song or poem. It can even refer to sad, but non-vocal music -- as when Tennessee Williams references background music in A Streetcar Named Desire.