reckoner

plural reckoners

1. One who reckons.

   middle-aged (-ajd), between youth and old age, variously reckoned to suit the reckoner

   1959 [1901], “middle-aged”, in William Geddie, editor, Chambers Twentieth Century Dictionary, revised edition, page 672

   2 more examples

   “No. Not quite a month.—It is only four weeks to-morrow since I left Mansfield.” “You are a most accurate and honest reckoner. I should call that a month.”

   1814 May 9, [Jane Austen], chapter XLII, in Mansfield Park: […], volume I, London: […] [George Sidney] for T[homas] Egerton, […], →OCLC

   Some experienced New York political reckoners think the real race, in the end, will be between Democrat Richard Ottinger and Mr. Buckley.

   1970 July 25, Anthony Lewis, “The Charm of Mr. Buckley”, in The New York Times, →ISSN, archived from the original on 08 Oct 2022

2. archaicAn accountant; one who computes or calculates.
3. An ordinator.