Antonyms of adj guileless

1 sense of guileless

Sense 1
guileless, transparent -- (free of deceit)

INDIRECT (VIA straight) -> crooked, corrupt -- (not straight; dishonest or immoral or evasive)

Similarity of adj guileless

1 sense of guileless

Sense 1
guileless, transparent -- (free of deceit)
       => straight (vs. crooked), square -- (characterized by honesty and fairness; "straight dealing"; "a square deal")