dissimulate (v.)

early 15c., dissimulaten, "conceal under false appearances, cause to appear different from the reality," from Latin dissimulatus, past participle of dissimulare "to disguise, hide, conceal, keep secret," from dis- (see dis-) + simulare "to make like, imitate, copy, represent," from stem of similis "like, resembling, of the same kind" (see similar). Intransitive sense of "practice pretense, feign" is from 1796. Related: Dissimulated; dissimulating. Earlier was dissimule (late 14c.), transitive and intransitive, from Old French dissimuler.