the.com/dissimulation

means The act of concealing your true feelings or intentions behind a false, calm appearance — pretending not to feel what you feel.

from From Latin dissimulare, 'to disguise, conceal, pretend not to see' — built from dis- (reversal, undoing) plus simulare, 'to make like, feign,' the same root that gives us simulate. So where simulation puts on a false front, dissimulation's prefix doubles down, hiding what's real rather than just mimicking what isn't. It passed into English through Old French in the medieval period, already carrying its courtly, careful sense of concealment.