Definition of cretinous in US English:

cretinous

adjective

  • 1offensive, informal Foolish or stupid.

  • 2Medicine
    dated Physically deformed and having learning disabilities as a result of congenital thyroid deficiency.

Origin

Mid 19th century: from cretin + -ous.

Pronunciation

cretinous

/ˈkrēt(ə)nəs//ˈkrit(ə)nəs/