clog

Concise Oxford English Dictionary © 2008 Oxford University Press:
clog/klɒɡ/

▶noun

• 1 a shoe with a thick wooden sole.

• 2 an obstacle or impediment.

▶verb (clogs, clogging, clogged) (often clog up) block or become blocked.

– origin ME (in the sense ‘block of wood to impede an animal's movement’): of unknown origin.