seize up /ˌsiːz ˈʌp/verb 3seize-up noun 1forms 4 verb3 •To stop working suddenly, and become impossible to start again.My car seized up this morning. So I had to catch the bus. •(figurative) To stop functioning; to come to a halt.Iceland's foreign currency market has seized up after the three largest banks collapsed. •To stiffen or become tight and difficult to move.It was hard to write as my fingers had seized up with the cold weather. seize-up noun1 •Stillstand, slowdown.Growth in the UK service sector slowed last month amid a “seize-up” in activity as companies put projects on hold in the run-up to the general election. — 2024 formsseized up · seizing up · seizes up · seize-ups