lag

Synonyms: be behind dally dawdle decrease dillydally diminish drag drag one’s feet ebb fail fall off falter flag get no place fast hang back hobble idle inch inch along jelly limp linger loiter lose strength lounge plod poke procrastinate put off retard saunter shuffle slacken slouch slow slow up stagger stay straggle tail tarry tool trail trudge wane

Antonyms: run rush