Just read The Rivals again, wonderful play. The most memorable character is, of course, Mrs Malaprop. Usually the word she is groping for is pretty easy to spot ("like an allegory on the banks of the Nile”, “he is the very pineapple of politeness!") but sometimes one is left groping alongside her. Take these examples.
Sir Anthony: Objection! Let him object if he dare! ........ My process was always very simple: in their younger day ‘twas ‘Jack, do this’; - if he demurred, I knocked him down - and if he grumbled at that I always sent him out of the room.
Mrs Malaprop: Aye, and the properest way, o’ my conscience! nothing is so conciliating to young people as severity. - Well, Sir Anthony, I shall give Mr Acres his discharge, and prepare Lydia to receive your son’s invocations ........
Mrs Malaprop: No! Captain Absolute is indeed a fine gentleman! ..................... Then he’s so well-bred, so full of alacrity and adulation! and has so much to say for himself: in such good language too! His physiognomy so grammatical!
Anyone care to take a stab at the words she means? (Not sure with that last one whether one or both are malapropisms).
BTW Mrs Slipslop in Henry Fielding’s novel Joseph Andrews (1742) had exactly the same propensity for getting her words wrong, as did Dogberry, the constable in Much Ado About Nothing. There’s a long comic tradition of such characters stretching back to Aristophanes and Plautus.