Bigfoot

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1950s: from the size of the creature's footprints (the term is recorded from the mid 19th century as a nickname for a person with large feet).

August/September 1958, [1] originally Big Foot, big +‎ foot, relating to the large size of its supposed footprints relative to human footprints.

bigfoot (n.)

supposed elusive man-like creature of the Pacific Northwest, 1963, from big (adj.) + foot (n.).