두근거려요 · 두근거렸어요 · 두근거릴 거예요 · 두근거리는 (+noun)
to pound, to throb, to flutter (of the heart)
Example
발표 전에 가슴이 너무 두근거렸어요.
My heart was pounding so hard before the presentation.
Word parts
From 두근두근, the sound of a racing heart, plus -거리다 'keep doing'.
Good to know
The subject is usually 가슴 or 심장: 가슴이 두근거려요 'My heart is racing.'