Crambo is described as “a play at short verses in which a word is given, and the parties contend who can find most rhymes to it.”
This text comes from a footnote on a diary entry in the 1893 edition edited by Henry B. Wheatley.
Cra'mbo. n.f [a cant word, probably without etymology.] A play at which one gives a word, to which another finds a rhyme; a rhyme.
So Mævius, when he drain'd his skull
To celebrate some suburb trull,
His similes in order set,
And ev'ry crambo he could get. Swift.
---A Dictionary of the English Language. Samuel Johnson, 1755.
Chart showing the number of references in each month of the diary’s entries.