1. adverb /neɪ/
no.
2. conjunction /neɪ/
or even, or more like, or should I say. Introduces a stronger and more appropriate expression than the preceding one.
And even in our wildest and most wandering reveries, nay in our very dreams, we shall find, if we reflect, that the imagination ran not altogether at adventures,
3. noun /neɪ/
a) A vote against.
I vote nay, even though the motion is popular, because I would rather be right than popular.
b) A person who voted against.
The vote is 4 in favor and 20 opposed, the nays have it.
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