I have a usage related doubt about using 'Dark' in the following sentence:
Each time, when he switches on the light, he is surprised how it vanishes ______ completely.
'Darkness' fits well here, but does 'dark' work too, as it is also a noun?
English Language & Usage Stack Exchange is a question and answer site for linguists, etymologists, and serious English language enthusiasts. It only takes a minute to sign up.Sign up to join this community
Most importantly, what is incorrect in both the examples is that 'vanish' is an intransitive verb. It cannot be used transitively as you have done.
'He vanished the coin' does not make sense, as it is the coin which 'vanishes'. So one needs to say 'he made the coin vanish'.
Similarly you cannot say '...it vanishes the darkness completely'. You need to say '...the darkness vanishes completely', or '...it makes the darkness vanish completely'.
On the more minor point about dark v darkness, I think 'darkness' is the more literate and elegant word to use. However I do not rule out that many people would say 'it makes the dark vanish'. 'Dark' is certainly used as a noun as well an adjective - but 'darkness' is better.
Making the assumption that you have left out an article (the) after vanishes, I would say either is correct.
It is unusual in English to use vanish as verb with an object in this manner, but it is a valid usage. See definition #5. The meaning becomes to cause to disappear. See this search page entitled How to vanish a coin.
Each time, when he switches on the light, he is surprised how it vanishes the darkness completely.
Each time, when he switches on the light, he is surprised how it vanishes the dark completely.
Darkness is a noun. Dark is a noun. They are effectively synonyms of one another.
That said, to my native ear, darkness has a "better ring to it". But, there is no grammatical reason why this is true.