Definition of nice-but-dim in English:

nice-but-dim

adjective

British
informal
  • Designating a person regarded as foolish, incompetent, and ingenuous, while also being utterly good-natured and unmalicious.

Origin

1980s; earliest use found in The Guardian. From nice + but + dim.

Pronunciation

nice-but-dim

/ˌnʌɪs bət ˈdɪm/