reckoning without one's host

Verb

reckon without one's host (third-person singular simple present reckons without one's host, present participle reckoning without one's host, simple past and past participle reckoned without one's host)

1. (idiomatic, rare) To calculate one's bill without checking with the host or landlord; hence, to come to false conclusions, to miscalculate.
   • He had flattered himself, that this gentlewoman would decline the proposal, as she was a person seemingly of a demure disposition, who had been born and bred in the city, where such diversions are looked upon as scenes of lewdness and debauchery. For once, however, he reckoned without his host...1751, [Tobias] Smollett, The Adventures of Peregrine Pickle […], volume (please specify |volume=I to IV), London: Harrison and Co., […], →OCLC