How to hide record.php custom button

Hello Technical Team , 

Can you clarify if there are any conditions for the button to be hidden ?
Will this depend on any role or record validation? 

If it's something that you just want to hide from regular users, you could consider restricting the button to admin users with the following property: 

    'acl_action' => 'admin',

Thank you Andre, for your reply,

yes its depends on particular role, for example i need to hide the button only for "abc role"

and please share also the syntax to hide a button

Thank you Andre, for your reply,

yes its depends on particular role, for example i need to hide the button only for "abc role"

and please share also the syntax to hide a button