Sneaking
Part of speech: verb
Definition: To creep or go stealthily; to come or go while trying to avoid detection, as a person who does not wish to be seen.
Example sentence: I've had this sneaking feeling throughout the game that it's there to be won.
Concealed
Part of speech: verb
Definition: To hide something from view or from public knowledge, to try to keep something secret.
Example sentence: Anger ventilated often hurries towards forgiveness; anger concealed often hardens into revenge.