Fatal Error cant log in to admin or site anymore

here is the error I got
Fatal error: Call to undefined function is_admin_bar_showing() in /home2/hustleal/public_html/jaymystic/wp-content/plugins/admin-bar-minimiser/admin-bar-minimiser.php on line 47

now I cant get to my admin or site to undo the mistake. I am rookie at this and need helping unscrewing this one. Please help!!