How many letters does the top answer for “to an exceedingly great extent or degree” have?

The most common answer is immensely (9 letters).

Crossword clue: to an exceedingly great extent or degree

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

immensely 9 letters wn-def

to an exceedingly great extent or degree

vastly 6 letters wn-def

to an exceedingly great extent or degree

to a great degree or extent 75% similar → much

to a great extent or degree 75% similar → considerably, substantially

to a very great degree or extent 60% similar → lots

to a very great extent or degree 60% similar → so

to a great degree 50% similar → sorely, widely

to the degree or extent that 50% similar → insofar