to tremble inwardly (or palpitate), i.e. (figuratively) be (causative, make) (suddenly) alarmed or agitated; by implication to hasten anxiously
be (make) affrighted (afraid, amazed, dismayed, rash), (be, get, make) haste(-n, -y, -ily), (give) speedy(-ily), thrust out, trouble, vex.
a primitive root;