plod

Concise Oxford English Dictionary © 2008 Oxford University Press:
plod/plɒd/

▶verb (plods, plodding, plodded) walk doggedly and slowly with heavy steps.

■ work slowly and perseveringly at a dull task.

▶noun

• 1 a slow, heavy walk.

• 2 (also PC Plod) Brit. informal a police officer.

– derivatives
plodder noun,
plodding adjective,
ploddingly adverb.

– origin C16: prob. symbolic of a heavy gait.