Q: I’m curious about the history of “thunk,” the past tense of “think.” I use it for fun in conversation, but my girlfriend swears it’s gibberish. Help me out, please.
A: The word “thunk” is a humorous past tense or past-participle for the verb “think.” The Oxford English Dictionary calls it a jocular or dialectal usage. The standard past tense or past-participle is “thought.”
The first published use cited in the OED is from C. Clough Robinson’s A Glossary of Words Pertaining to the Dialect of Mid-Yorkshire (1876). Robinson spelled it “thuongk” and noted that in the past tense “it is of constant occurrence.”
Although the Yorkshire citation is a dialectal usage, the more common use of “thunk” these days is as a jocular past participle, the form of a verb used with “have” or “had.”
The “have” or “had” in these “thunk” expressions is often reduced to “uh” or “a,” as in “Who’d uh thunk it?” instead of “Who’d have thunk it?”
In fact, the OED has a remarkably modern-sounding 1887 citation for the “a” version from a New Orleans newspaper called the Lantern: “Who’d a thunk it?”