otter UK /ˈɒtə/US /ˈɑtɚ/ noun4 •An aquatic or marine carnivorous mammal in the subfamily Lutrinae. •(slang) A hairy man with a slender physique, in contrast with a bear, who is more thickset. •The flesh or fur of this animal •(no longer used) annatto (dye) formsotters