What are the best answers for “of a vivid red to reddish-orange color”?

cinnabar, vermilion, vermillion.

How many letters does the top answer for “of a vivid red to reddish-orange color” have?

The most common answer is cinnabar (8 letters).

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

cinnabar 8 letters wn-def

large red-and-black European moth; larvae feed on leaves of ragwort; introduced into United States to control ragwort

vermilion 9 letters wn-def

a variable color that is vivid red but sometimes with an orange tinge

vermillion 10 letters wn-def

of a vivid red to reddish-orange color

a reddish to vivid orange color 80% similar → tangerine

a deep and vivid red color 50% similar → crimson

of a strong reddish orange color 50% similar → tangerine