i-adjective
hard to imagine; unlikely; doubtful
Expresses that something is difficult to conceive or very improbable. Often used when the speaker finds a situation or outcome hard to believe.
彼がそんなことをするとは考えにくい。
It's hard to imagine him doing such a thing.
この計画が成功するとは考えにくい。
It's very doubtful that this plan will succeed.
Compound of the verb stem 考え (from 考える 'to think') + the auxiliary adjective にくい 'difficult to do'. The spelling 考え悪い is a rare ateji usage.