Answer
Even
Work Step by Step
When $x\ge0,$
$f(x)=x|x|=x\times x=x^{2}$
$f(-x)=-x|-x|=-x\times x=-x^{2}$
$f(-x)=-f(x)$
When $x\lt0,$
$f(x)=x|x|=x\times-x=-x^{2}$
$f(-x)=-x|-x|=-x\times-x=x^{2}$
$f(-x)=-f(x)$
$\therefore f(x)$ is even.