To hide under a false appearance. (Merriam – Webster)
To disguise or conceal under a false appearance; dissemble: (Dictionary.com)
Conceal or disguise (one’s thoughts, feelings, or character) (Oxford Dictionaries)
When people dissimulate, they hide their true feelings, intentions, or nature. (Collins Dictionary)
To hide your real feelings, character, or intentions: (Cambridge Dictionary)
Dissimulation and Deceit in Early Modern Europe.
Phenomenology of malingering, dissimulation and aspiration.