Dissemble / dih-sem-buhl / verb
1. To conceal one’s true motives, thoughts, etc., by some pretense; speak or act hypocritically.
2. To give a false or misleading appearance to; conceal the truth or real nature of: to dissemble one’s incompetence in business.
He counted heavily on his ability to dissemble , knowing that every decent lawyer had at least several drops of dissimulation in his blood.
— Elizabeth George, Missing Joseph, 1993
Dissemble comes from late Middle English dissemile, dissimill, an alteration of the verb dissimule (from Old French dissimuler “to keep one’s intentions hidden,” from Latin dissimulāre, “to disguise or conceal one’s thoughts”), and associated in form with the noun semblance and the obsolete verb semble (from Old French sembler, from Latin similāre and simulāre “to pretend”). Dissemble entered English in the sense “to pass over, ignore, neglect” in the 16th century.