na-adjective, noun which may take the genitive case particle 'no', noun
worst of the worst; despicable; extremely bad
Emphatic expression combining 最低 and 最悪 to describe something or someone as utterly terrible, contemptible, or the absolute worst. Often used in casual, emotional speech.
あの映画は最低最悪だった。
That movie was the absolute worst.
彼の態度は最低最悪だ。
His attitude is despicable.
最悪 means 'the worst' and is commonly used on its own; 最低最悪 is a stronger, more emotional compound.
Compound of 最低 (lowest, worst) and 最悪 (worst). The exact origin is uncertain, but it likely emerged as an emphatic colloquial expression.