Bulma class: .is-radiusless

                        <div class="box is-radiusless">
   No radius box
</div>
                    

Preview

No radius box

More in Bulma Helpers

is-clearfix
is-pulled-left
is-pulled-right
is-marginless
is-paddingless
is-overlay
is-clipped
-shadowless
is-unselectable
is-invisible
is-hidden
is-sr-only
is-relative