bear ill will (/malice); bent on doing evil;be up to no good;cherish(/harbour)evil designs;have bad intentions;with hidden intent; with sinister (/ulterior) designs(/motives) ? 我覺得他們真是～，我如果不先采取措施，后害實(shí)在無窮。(愛新覺羅·溥儀《我的前半生》150)I now felt that they were completely unreliable and that if I did not strike first there would be no end of trouble.
居心叵測ju xin po ce
with sinister design
居心叵測
with sinister design;with ulterior motives
居心叵測jū xīn pǒ cè
居心：存心；叵：不可；測：推測。存心險(xiǎn)惡，難以推測。with concealed intentions, bent on doing evil, cherish dark designs