C2 noun /ˈspuːnərɪzəm/
spoonerism
spounérisme
Meaning
A verbal error in which the initial sounds of words are swapped to create a humorous effect.
Example
He made a spoonerism by saying 'queer old dean' instead of 'dear old queen'.
Il a fait un spounérisme en disant 'vieux doyen bizarre' au lieu de 'vieille reine chère'.