An undocumented way of accessing a system or software, usually used by hackers to bypass security.
"The attacker installed a backdoor to access the system at any time without being detected."
to decide or act as the situation develops
to be able to make quick decisions and act quickly, especial...
to betray someone for personal gain
to feel nervous or hesitant about something
to take responsibility for something bad.
completely exhausted or tired due to overwork