Yes, it is an adverb. it is the adverb form of doubtful (doubting).
Doubtfully.
The adjective form of doubtfully is doubtful.
doubtfully, uncertainly
adverb is word that modified a verb,adjective.or other adverb
actually, there are 4 types of adverb.1. adverb of manner2. adverb of time3. adverb of place4. adverb of frequency
Doubtfully.
Doubtfully
Doubtfully is the correct spelling.
The adjective form of doubtfully is doubtful.
The professor raised his eyebrows, showing how doubtfully he was receiving my explanation.
Doubtfully
doubtfully, uncertainly
if you say you will become a millionaire i will doubtfully say no. it means i dont think something will happen or i dont think you will do something.
Suspiciously, distrustfully, doubtfully.
Antonyms: doubtfully, gloomily, hopelessly
The opposite could be unsure, or uncertain.
Doubtfully. They have to be the same.