Nouns

(n)sorrowan emotion of great sadness associated with loss or bereavement“he tried to express his sorrow at her loss”
(n)sorrow, regret, rue, ruefulnesssadness associated with some wrong done or some disappointment“he drank to drown his sorrows”, “he wrote a note expressing his regret”, “to his rue, the error cost him the game”
(n)grief, sorrowsomething that causes great unhappiness“her death was a great grief to John”
(n)sadness, sorrow, sorrowfulnessthe state of being sad“she tired of his perpetual sadness”

Verbs

(v)grieve, sorrowfeel grief