How many letters does the top answer for “prevent the progress or free movement of” have?

The most common answer is halter (6 letters).

Crossword clue: prevent the progress or free movement of

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

halter 6 letters wn-def

rope or canvas headgear for a horse, with a rope for leading

hamper 6 letters wn-def

prevent the progress or free movement of