Clandestineness refers to the state or quality of being secretive or concealed. There are several synonyms for this word such as secrecy, stealth, furtiveness, surreptitiousness, and underhandness. Secrecy implies keeping things hidden or unknown, while stealth involves moving cautiously and quietly to avoid notice. Furtiveness and surreptitiousness are similar to stealth but imply a shadier or more illegitimate motive. Underhandness suggests deceptive or dishonest tactics. These synonyms all suggest a sense of operating in secret or with a hidden agenda, which may be motivated by a desire to avoid detection or repercussions.