noun
orangutan
Literary or old-fashioned term for orangutan; in modern Japanese, オランウータン is far more common.
昔の文献では、猩々はオランウータンを指すことがある。
In old documents, 猩々 sometimes refers to the orangutan.
noun
Figurative use likening a person who drinks heavily to the mythical red-faced, sake-loving 猩々 creature.
彼は毎晩のように飲んでいる、まったくの猩々だ。
He drinks almost every night; he's a total heavy drinker.
Originally a mythical creature in Chinese and Japanese folklore, depicted as a red-faced, sake-loving being. The 'orangutan' sense derives from early zoological naming, and the 'heavy drinker' sense is a figurative extension from the mythical creature's love of alcohol.