E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Tonans.
Delirium tonans. Loud talk, exaggeration, gasconade. Blackwood’s Magazine (1869) introduced the expression in the following clause:—
1
“Irishmen are the victims of that terrible malady that is characterised by a sort of subacute raving, and may, for want of a better name, be called ‘delirium tonans.’”
