USA 1920: ‘to have the brains of a goldfish’ (to have limited intelligence)—USA, 1958: ‘to have the memory of a goldfish’ (to be unable to retain information or memories for any significant length of time)
American English, 1874—used in particular of stupidity, as in ‘dumb as a bag of hammers’ and variants—the underlying notion is probably that anything is dumb that does all the hard work
the principle that, where an effective legal system is absent or does not apply, brute strength and self-interested ruthlessness are what determine success, ownership, etc.—USA, 1878—predates Kipling’s Jungle book
Britain, 1747: dew of the kind that settles on mountains—Scotland, 1816: whisky or other spirit, especially when home-made or illicit (originally in reference to whisky distilled in the Highlands, i.e., in the mountainous region of Scotland)
USA, 1977—petroleum, and any liquid derived from petroleum used in a vehicle powered by an internal-combustion engine—perhaps from popular association of ‘dinosaur’ with ‘fossil fuel’
UK, 1817—a blank book in which pictures, newspaper cuttings, and the like are pasted for preservation—hence also (UK, 1821) used as the title of a printed book of miscellaneous contents
British, dialectal, 1828: the break of day, i.e., the dawn chorus, with humorous allusion to a small passerine breaking wind—later also: an insignificant person or thing
UK, late 1980s—the adverb ‘o’clock’ is colloquially and humorously used with adjectives to denote an unreasonably, excessively or inconveniently early or late hour—as in ‘stupid o’clock’, ‘silly o’clock’, etc.