Definition of hang open:
(v) :
(chiefly imperative) To wait a moment.
(v) :
To hold, grasp, or grip.
(v) :
To depend upon.
(v) :
To persevere.
(v) :
To continually believe in something; to have faith in.
(v) :
To pay close attention to, or regard with (possibly obsequious) admiration.