adjective

showing a skilful use of underhand tactics to achieve goals.

he’s as devious as a politician needs to be

underhand,underhanded,deceitful,dishonest,dishonourable,disreputable,unethical,unprincipled,immoral,unscrupulous,fraudulent,cheating,dubious,dirty,unfair,treacherous,duplicitous,double-dealing,Janus-faced,below the belt,two-timing,two-faced,unsporting,unsportsmanlike,crafty,cunning,calculating,artful,conniving,scheming,designing,sly,wily,guileful,tricky,sneaky,sneaking,furtive,secret,secretive,clandestine,surreptitious,covert,veiled,shrouded,cloak-and-dagger,hugger-mugger,hole-and-corner,hidden,back-alley,backstairs,under the table,conspiratorial,snide,snidey,crooked,shady,bent,low-down,murky,fishy,dodgy,shonky,slim