vastly

Vastly is an adverb that indicates a very great extent, amount, or degree. It is used to modify verbs, adjectives, or other adverbs. Common collocations include vastly different, vastly improved, vastly more expensive, and vastly oversimplified. For example: "The new model is vastly more efficient than the old one." "The region is vastly underdeveloped compared with urban centers." It can emphasize scale in formal and informal writing, but it can sound emphatic or promotional in marketing contexts.

Etymology follows the path of many adverbs formed from adjectives: vastly derives from the adjective vast, which itself comes from Old French vaste, ultimately from Latin vastus meaning empty, wasteful, or large. The suffix -ly converts the word into an adverb.

Usage notes indicate that vastly is widely understood across English varieties. It often connotes substantial change or difference and is common in contemporary writing. It can be used with adjectives, participles, or other modifiers, but may seem exaggerated in neutral prose; in such contexts, words like greatly or significantly might be preferred.

See also: vast as an adjective; greatly; extremely; enormously; hugely.