(fishing, obsolete) A fish that is large and old, especially one that has algae growing on its back; a mossback.
(informal) A person with old-fashioned views; hence, one who is very conservative or reactionary; a mossback.
(informal, historical, obsolete) Synonym of mossback (“a person who stayed hidden to evade conscription (especially by the Confederate States Army) during the American Civil War (1861–1865)”)
(obsolete) The menhaden, mossbanker, or mossbunker, a marine fish of the genus Brevoortia or Ethmidium.