leopard cannot change his spots

a leopard can't change its spots

proverb One will stay true to one's nature, even if one pretends or claims otherwise. After our breakup, he came crawling back, trying to convince me that he'd changed, but I know that a leopard can't change its spots.
See also: change, leopard, spot
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

leopard cannot change his spots

Prov. One cannot change the basic way one is. Bill may say he'll stop being so jealous after Cindy marries him, but I doubt he will. A leopard can't change his spots.
See also: cannot, change, leopard, spot
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
See also:
References in periodicals archive ?
Is this proof that a leopard cannot change his spots? Perhaps expecting Boris to change his ways is like expecting the whole of the English nation to give up their traditional hatred of the French.
He said: "A leopard cannot change his spots and I don't see at this stage why I should.