All 4 Uses

lament
in
A Room With A View
(Auto-generated)

His mysterious persecution of Mr. Eager became relentless; the air rang with his threats and lamentations.†
Chpt 5

lamentations = passionate expressions of grief or sorrow
Miss Bartlett, who had intended to lament over the Emersons, was launched by this remark into unexpected thoughts.†
Chpt 5 *

lament = express grief or regret
It is lamentable, lamentable—incredible.†
Chpt 19

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.
It is lamentable, lamentable—incredible.†
Chpt 19

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.