na-adjective, noun
utterly lacking in ability; hopeless; useless; poor
Describes someone who is completely unskilled or hopeless at something; often used self-deprecatingly or to criticize. The から prefix intensifies the lack of ability.
私は料理がから下手で、卵もまともに焼けません。
I'm utterly hopeless at cooking; I can't even fry an egg properly.
彼はスポーツはから下手だが、勉強はできる。
He's completely useless at sports, but he's good at studying.
Compound of から (empty, void) and 下手 (unskillful). The exact historical derivation is uncertain, but the combination intensifies the meaning to 'completely lacking in skill'.