noun

• (chiefly Scotland) An Atlantic salmon, Salmo salar, especially a female after spawning.
• (Canada, US) Either of two dark-coloured fish of the west Atlantic, the tautog of New England (Tautoga onitis) and the black sea bass (Centropristis striata).
• (Australia, New Zealand) Any of various dark-coloured fishes of Australasia, especially the luderick (Girella tricuspidata), and a freshwater fish, Gadopsis marmoratus.
  "The creek was reputed to contain blackfish and Nathan […] arranged the extraordinary collection of American lures he had inherited from an uncle."

verb

• (fishing) To go fishing for blackfish.
  "Earlier (Caldwell and Caldwell 1971a), we concentrated on the blackfishing at St. Vincent, the fishery with which we were most familiar, and listed known localities of fishing for blackfish and other species in the southern Caribbean."

verb

• (Internet slang, derogatory, of a non-black person) To adopt signifiers of black identity (for example, by darkening the skin, or wearing traditionally black hairstyles).
  "Judging from not only various records of campus life but also the numerous Instagram accounts of women appearing as "black" personalities — a phenomenon known as "blackfishing" — many do not know better."