News (the free dictionary)
Definition: (verb) Provoke or stir up.
Synonyms: instigate, stir up, set off.
Usage: Those who incite riots should be held accountable for the damage they cause.
Definition: (verb) Worry unnecessarily or excessively.
Synonyms: fret, fuss.
Usage: I realize now that the things which used to niggle me did not really matter.
Definition: (noun) Bone linking the scapula and sternum.
Usage: He will be out for the rest of the season thanks to a broken clavicle.