軽愚 is read as けいぐ (keigu) and means moronity.
けいぐ
keigu
けいしょう
minor injury
けいそつ
rash
けいし
making light of
けいみょう
light and easy
けいきかんじゅう
light machine gun
けいび
slight
けいきんぞく
light metal
minor illness
けいじどうしゃけんさきょうかい
Light Motor Vehicle Inspection Organization
けいきんぞくせいひんきょうかい
Aluminium Products Association
けいげんぜいりつ
reduced tax rate
けいどにんしきしょうがい
mild cognitive impairment