The antonyms for the phrase "more above board" can include "dishonest," "deceitful," "fraudulent," "unethical," and "unscrupulous." These terms suggest that a person or a situation is not open, honest, or transparent, and that there may be ulterior motives or hidden agendas at play. Actions or decisions made by individuals who are not "above board" can lead to negative consequences, such as a loss of trust, legal consequences, or damage to relationships. It is important to strive for integrity in all dealings and to avoid any actions that could be interpreted as less than honest.