no more Mr Nice Guy

no more Mr. Nice Guy

An expression indicating that one is no longer going to behave in a pleasant, tolerant, or carefree manner. OK, no more Mr. Nice Guy. The next person to speak out of turn gets detention.
See also: guy, more, nice, no
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

no more Mr Nice Guy

used to suggest that you will stop being lenient and begin to adopt more severe measures.
See also: guy, more, Mr, nice, no
Farlex Partner Idioms Dictionary © Farlex 2017
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References in periodicals archive ?
No more Mr Nice Guy: Sacked Apprentice candidate Christopher Farrell.
Although he doesn't smoke or drink very often, he says from now on it's no more Mr Nice Guy.
And he dumps his "no more Mr Nice Guy" catch phrase for "no more Mr Spice Guy".
Perhaps this is his way of telling us: No more Mr Nice Guy.
Aston Villa striker Marcus Allback says that it's got to be 'No more Mr Nice Guys' if David O'Leary's struggling side are to climb the Premiership table.