Out of $o-$nitrophenol and $o-$cresol,which is more acidic?

(N/A) The presence of an electron-withdrawing group ($-I$ or $-M$ effect) stabilizes the phenoxide ion,thereby increasing the acidic strength of the phenol. Conversely,an electron-donating group ($+I$ or $+M$ effect) destabilizes the phenoxide ion,decreasing the acidic strength.
In $o-$nitrophenol,the $-NO_2$ group exerts a strong $-I$ and $-M$ effect,which stabilizes the phenoxide ion.
In $o-$cresol,the $-CH_3$ group exerts a $+I$ effect,which destabilizes the phenoxide ion.
Therefore,$o-$nitrophenol is more acidic than $o-$cresol.