foo

Etymology 1

From Mandarin 府 (fǔ).

noun

1. (historical, obsolete) Alternative form of fu: an administrative subdivision of imperial China; the capital of such divisions.

Etymology 2

(fú, 福)]] From Chinese 福 (fú, “fortunate; prosperity, good luck”), via its use as 福星 (Fúxīng, “Jupiter”) in Chinese statues of the Three Lucky Stars, picked up from c. 1935 as a nonsense word in Bill Holman's Smokey Stover comic strip, whence it was picked up by Pogo, Looney Tunes, and others. Used by Jack Speer as the fannish ghod of mimeography. Popularized in computing contexts by the Tech Model Railroad Club's 1959 Dictionary of the TMRC Language, which incorporated it into a parody of the Hindu chant om mani padme hum, possibly under the influence of WWII military slang FUBAR, which had been repopularized by Joseph Heller's Catch-22.

noun

1. (programming) A metasyntactic variable used to represent an unspecified entity. If part of a series of such entities, it is often the first in the series, and followed immediately by bar.
   Suppose we have two objects, foo and bar.
2. (fandom slang) Alternative letter-case form of Foo (“placeholder god”)

Etymology 3

A minced form of fuck.

intj

1. Expression of disappointment or disgust.
   Oh foo – the cake burnt!

Etymology 4

noun

1. (slang) Pronunciation spelling of fool.
   [page 10:] "I knew you'd be scared," Reggie laughed. "What are you doin', foo? You must be crazy. You don't scare me." "Then why did you almost fall out of that chair? I scare everyone." [page 38:] "This is coo," said Fred. "It's almost like being there." "We are there, foo!" said Reggie as the boys slapped palms. 2020, J. Lewis Johnson, A Dark Night in the Fieldhouse