dwindling

(noun) a becoming gradually less. Synonyms: dwindling away. Example: "There is no greater sadness that the dwindling away of a family."

(verb) become smaller or lose substance. Synonyms: dwindle, dwindle away, dwindle down. Example: "Her savings dwindled down."

(adj) gradually decreasing until little remains. Synonyms: tapering, tapering off.