adverb
The most common modern use. It appears with a negative predicate such as ない, ぬ, ません, or a negative-feeling expression, emphasizing that there is no change, progress, effect, concern, etc.
雨は一向にやまない。
The rain shows no sign of stopping at all.
説明を聞いても、一向に分からなかった。
Even after hearing the explanation, I did not understand it at all.
adverb
completely; absolutely; totally
An emphatic degree adverb meaning fully or absolutely. In modern Japanese it often occurs with predicates that are positive in form but express being unaffected, unconcerned, or acceptable, such as 平気だ.
彼は批判されても一向に平気な顔をしていた。
Even when criticized, he looked completely unbothered.
adverb
earnestly; intently; single-mindedly
Rare and old-fashioned as an adverb meaning to do something single-mindedly or intently; modern Japanese would more often use ひたすら, 一心に, or 熱心に.
古い文章では、「一向に念仏を唱える」が「ひたすら念仏を唱える」という意味で使われることがある。
In older writing, 一向に念仏を唱える can mean 'to chant prayers single-mindedly.'
A common modern word for 'single-mindedly' or 'earnestly'; it is the natural choice for the rare older 一向に sense meaning intently.
一向 is written with 一 'one' and 向 'direction, facing,' plus the adverbial particle に. The spelling is conventionally associated with the idea of being wholly in one direction or degree; the detailed historical development of each sense is not specified.