SLa 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’ 〔两个词的〕首音误置〔说话时误把两个单词的首音调换,造成滑稽效果,如把 show you to a seat 说成 sew you to a sheet〕
Originspoonerism
(1900-2000) William Spooner (1844-1930), British university teacher who supposedly often made such mistakes