n. 25B6; verb
she was fretting about Jonathan : WORRY, be anxious, feel uneasy, be distressed, be upset, upset oneself, concern oneself; agonize, sigh, pine, brood, eat one's heart out.
his absence began to fret her : TROUBLE, bother, concern, perturb, disturb, disquiet, disconcert, distress, upset, alarm, panic, agitate; informal eat away at.