Nouns

(n)sinkinga descent as through liquid (especially through water)“they still talk about the sinking of the Titanic”
(n)sinkinga slow fall or decline (as for lack of strength)“after several hours of sinking an unexpected rally rescued the market”, “he could not control the sinking of his legs”
(n)sinking, sinking feelinga feeling caused by uneasiness or apprehension“with a sinking heart”, “a sinking feeling in the pit of my stomach”