The phrase ‘footloose and fancy-free’ means ‘not committed or tied to anyone or anything’—it appeared in the 1860s only, in U.S. political contexts, although each of its elements dates from the 17th century.
USA, 1917 (with ‘footie’): to touch somebody’s foot lightly with one’s own foot, especially under a table, as a playful expression of romantic interest—hence also, figuratively: to have underhanded dealings with somebody
UK, 1945—‘demob happy’: feeling elated in anticipation of demobilisation from the armed forces—hence: in anticipation of the end of a job, assignment, etc.—in extended use: in anticipation of the end of any onerous or unpleasant period
UK, 1823—‘a hurried departure at night, especially from rented accommodation to avoid payment of rent owed’—‘flit’, noun use of ‘to flit’, originally used in Scotland and Northern England to mean ‘to move house or leave one’s home’
UK, 1831—to startle or upset a sedate or conventionally-minded community—most probably from the following lines in The Tragedy of Coriolanus (circa 1607), by William Shakespeare: “like an eagle in a dove-cote, I | Flutter’d your Volscians in Corioli”
USA, Boston Morning Post, 26 May 1834—‘Dutch uncle’: a person giving firm but benevolent advice—unknown origin—perhaps an allusion to Calvinistic sternness
British English, armed forces, 1936—With reference to the bluebottle fly, the colloquial phrase ‘like a blue-arsed fly’ is used to describe someone engaged in constant, frantic activity or movement.
used to convey that something is unvaryingly familiar or drearily predictable—first recorded (USA, 1963) as the title of a song by Roger Kellaway, American jazz pianist and composer
USA, 1910s—originated in horse racing: ‘under wraps’ is used of a horse that the rider is holding back and intentionally keeping from running at top speed—not from the wrapping placed over newly developed machines before their official launch
USA, 1930—‘to crawl, or to come, out of the woodwork’: of an unpleasant or unwelcome person or thing, to come out of hiding, to emerge from obscurity; the image is of vermin or insects crawling out of crevices or other hidden places in a building