verb

conceal or disguise one’s true feelings or beliefs.

an honest, sincere person with no need to dissemble

dissimulate,pretend,deceive,feign,act,masquerade,sham,fake,bluff,counterfeit,pose,posture,hide one’s feelings,be dishonest,put on a false front,lie,cover up,conceal,disguise,hide,mask,veil,shroud