reduplication + ~しい (intensified adjective)

A productive pattern: a one-syllable adjective root (or noun) reduplicated with the ~々 iteration mark + the suffix しい, forming an i-adjective for an intensified, often pejorative, observable quality. 若々しい ('youthful'), 弱々しい ('weak-looking'), 痛々しい ('painful to see'), 騒々しい ('noisy'), 毒々しい ('gaudy'), 馬鹿馬鹿しい ('utterly absurd').