(intransitive) To practise deception by concealment or omission or by feigning a false appearance.
1912 Booth Tarkington, The Flirt, Chapter 13But 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.
(transitive) To hide or disguise by adopting a false appearance.
Eliot Middlemarch|3Public feeling required the meagreness of nature to be dissimulated by tall barricades of frizzed curls and bows.
(transitive, rare) To connive at; to wink at; to pretend not to notice.
1533 John Bourchier (Lord Berners), The Golden Boke of Marcus Aurelius 9: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.
