凡庸愚昧 - JP-EN Jisho

凡(ぼん)庸(よう)愚(ぐ)昧(まい)

noun (common) (futsuumeishi)adjectival nouns or quasi-adjectives (keiyodoshi)nouns which may take the genitive case particle 'no'

ordinary and ignorant; mediocre and stupid