Hide category

Hello ledraw,

if you are using the default category widget provided by WordPress, then you can use this solution for that

https://ww.wp.xz.cn/support/topic/excluding-category-from-widget?replies=4#post-2583723

or you can install an another widget and use that https://ww.wp.xz.cn/plugins/pro-categories-widget/

I hope this help you.