dissemble

(verb) make believe with the intent to deceive. Synonyms: feign, sham, pretend, affect. Examples: "He feigned that he was ill." "He shammed a headache."

(verb) hide under a false appearance. Synonyms: cloak, mask. Example: "He masked his disappointment."

(verb) behave unnaturally or affectedly. Synonyms: pretend, act. Example: "She's just acting."