馬鹿馬鹿しい

Etymology
+ adjective-forming suffix. Attested from at least 1772, but likely older, as the suffix was much more productive earlier, such as during the  (794–1185).

Adjective

 * 1)  extremely foolish, ridiculous, silly contrary to reason or propriety
 * 2)  blatant, extreme, outrageous

Related terms

 * : foolish, stupid; a fool, an idiot
 * : like a fool, like an idiot