Etymology Inherited from Middle English dissimulaten, dissimilaten, from Latin dissimulātus + -en (“verb-forming suffix”), perfect passive participle of dissimulō (“to conceal, to pretend, to neglect”) (see -ate (verb-forming suffix)), from dissimilis (“unlike”) + -ō (verb-forming suffix). Compare the obsolete dissimule (“to conceal, disguise”), from Old French dissimuler (French dissimuler), ultimately from the same Latin root. Doublet of dissemble, dissimilate, and dissimule.
1
To practise deception by concealment or omission, or by feigning a false appearance; to dissemble.
But now, as he paced alone in his apartment, now that he was not upon exhibition, now when there was no eye to behold him, and there was no reason to dissimulate or veil a single thought or feeling, his look was anything but open; the last trace of frankness disappeared; the muscles at mouth and eyes shifted; lines and planes intermingled and altered subtly; there was a moment of misty transformation – and the face of another man emerged. It was the face of a man uninstructed in mercy; it was a shrewd and planning face: alert, resourceful, elaborately perceptive, and flawlessly hard.1913, Booth Tarkington, chapter 13, in The Flirt, Garden City, N.Y.: Doubleday, Page & Company, →OCLC, page 212:
2
To disguise or hide by adopting a false appearance; to dissemble.
[P]ublic feeling required the meagreness of nature to be dissimulated by tall barricades of frizzed curls and bows.1871, George Eliot [pseudonym; Mary Ann Evans], chapter III, in Middlemarch […], volume I, Edinburgh; London: William Blackwood and Sons, →OCLC, book I, page 38:
3
Rare To connive at; to wink at; to pretend not to notice.
That al thyng be forgiven to theim that be olde and broken, and to theim that be yonge and lusty to dissimulate for a time, and nothyng to be forgiuen to very yong children.1533 John Bourchier (Lord Berners), The Golden Boke of Marcus Aurelius 9
Etymology Inherited from Middle English dissimulat(e), dissimilat(e) (attested in Robert Henryson with an active sense, see the citation page), from dissimulātus, see Etymology 1 and -ate (adjective-forming suffix) for more.
Where they may win ought : by fayre diſimilate ſhow, There they flickar, and flatter, in fauer to grow.1556, John Heywood, chapter LXIII, in The Spider and the Flie. […], London: […] Tho[mas] Powell, →OCLC; republished as A[dolphus] W[illiam] Ward, editor, The Spider and the Flie. […] (Publications of the Spenser Society, New Series; 6), Manchester: […] [Charles E. Simms] for the Spenser Society, 1894, →OCLC, page 286: