nervous and unable to relax

She’s fretting about her exams. (NOTE: fret-ting – fretted)  noun the raised metal strip

bowed stringed instrument that is the highest member of the violin family; this instrument has four strings and a hollow body and an unfretted fingerboard and is played with a bow

To seize something with the teeth and bite or tear repeatedly, To touch or handle nervously or persistently, To attempt to deal with in a persistent or repeated manner, transitive verb_ To harass by pursuit and barking; to attack repeatedly; also, to tear or mangle with the teeth, To harass or beset with importunity, or with care an anxiety; to vex; to annoy; to torment; to tease; to fret; to trouble; to plague, Disturb the peace of mind of; afflict with mental agitation or distress, verb_ touch or rub constantly, disturb the peace of mind of; afflict with mental agitation or distress, be concerned with, noun_ a strong feeling of anxiety, something or someone that causes anxiety; a source of unhappiness, A state of undue solicitude; a state of disturbance from care and anxiety; vexation; anxiety; fret

A stringed instrument played with a bow, having four strings tuned at intervals of a fifth, an unfretted fingerboard, and a shallower body than the viol and capable of great flexibility in range, tone, and dynamics, The modern form of the smaller medieval viola da braccio, bowed stringed instrument that is the highest member of the violin family; this instrument has four strings and a hollow body and an unfretted fingerboard and is played with a bow

A musical instrument having a flat-backed rounded body that narrows in the middle, a long fretted neck, and usually six strings, played by strumming or plucking, A stringed instrument of music resembling the lute or the violin, but larger, and having six strings, three of silk covered with silver wire, and three of catgut, -- played upon with the fingers, verb_ rare To play the guitar