The word 'most conniving' implies a tendency to scheme or manipulate, but its antonyms convey very different meanings. 'Honest' and 'forthright' are two examples of antonyms for this phrase. Someone who is honest behaves with integrity and straightforwardness, avoiding deceit and trickery in their dealings with others. Similarly, a person who is forthright expresses themselves openly and directly, without guile or duplicity. Alternatively, 'simple' and 'straightforward' can be used as antonyms, indicating a lack of complexity or hidden motives. So, while conniving implies a certain level of intellectual cunning or subterfuge, its antonyms suggest a more straightforward, upfront approach to interpersonal relationships.