spoo ‧ ner ‧ is ‧ m /ˈspuːnərɪz ə m/ BrE AmE noun [countable]
[ Date: 1900-2000 ; Origin: William Spooner (1844-1930), British university teacher who supposedly often made such mistakes ]
a phrase in which the speaker accidentally exchanges the first sounds of two words, with a funny result, for example ‘sew you to a sheet’ instead of ‘show you to a seat’