借题发挥

借题发挥 [jiè tí fā huī]

1. ■ seize on some pretext or other to distort; give vent to one's pent-up feelings on some extraneous pretext; make an issue of; make use of a subject as a pretext for one's drawnout talk; make use of the subject under discussion to put over one's own ideas; play on the theme of ...; seize on an incident to exaggerate matters; seize upon a pretext and give vent to one's feelings; seize upon [take] some pretext and make a fuss