Last week A Word a Day (http://wordsmith.org/awad/awadmail.html) was listing new entries in the Oxford English Dictionary, and full monty was one of these. Anu at AWAD reported that the response was enormous, and included the following theories on the origin of the term, in order of popularity:

fuel up = F = fum

Full Monty n.

See monty, sense 2.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.

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