Imbecile

im·be·cile play_w(“I0043500″)

 (mb-sl, -sl)

n.

1. A stupid or silly person; a dolt.

2. A person whose mental acumen is well below par.

3. A person of moderate to severe mental retardation having a mental age of from three to seven years and generally being capable of some degree of communication and performance of simple tasks under supervision. The term belongs to a classification system no longer in use and is now considered offensive.

adj. also im·be·cil·ic (mb-slk)

1. Stupid; silly.

2. Well below par in mental acumen.