The word "most surreptitiousness" refers to being sneaky, secretive, and stealthy in one's actions or behavior. Some synonyms for this term include covert, clandestine, furtive, stealthy, sly, and underhanded. Each of these words represents the character traits of someone who is acting with the intent to conceal their actions or intentions. Covert refers to a hidden, discreet or secret action, while clandestine refers to a secret or hidden activity meant to be kept hidden from others. Furtive refers to a stealthy or secretive manner, while stealthy suggests a quiet or cautious approach. Sly refers to someone who is cunning or deceitful, while underhanded refers to someone who is dishonest or deceitful.