very boring or unexciting—‘(as) dull as ditchwater’ (1770)—the later phrase ‘(as) dull as dishwater’ (1832) is probably due to mispronunciation of ‘ditchwater’ in the original phrase
U.S. slang, 1908—the noun ‘beeswax’ is humorously substituted for the noun ‘business’ (i.e., things that are one’s concern), these two nouns sharing a similar-sounding initial syllable
USA, 1949—a person (originally and chiefly a girl or a woman) who is especially talkative—popularised from 1960 onwards by a proprietary name for a child’s talking doll manufactured by Mattel
to urinate—slang—2nd half of the 20th century—based on the sound /eɪn/, common to the verb, adjective and noun that compose it—‘main vein’ probably refers to the penis
UK, 1884—‘what a surprise!’—a borrowing from French—chiefly used ironically, to imply that a situation or event is unsurprising, typical or predictable
It has been said that ‘(as) right as a trivet’ an alteration of ‘(as) tight as a rivet’. But the latter phrase, which postdates the former, originally meant ‘extremely tight’, not ‘thoroughly or perfectly right’.
a Volkswagen car—USA, 1967—from the pronunciation of ‘VW’ (initialism from the name ‘Volkswagen’)—‘dub’: shortened form of the adjective ‘double’ in ‘double U’