In Early Modern English, nay was used to respond to a positive question, while no was used to respond to a negative question. Over time, this distinction disappeared.
- or even, or more like, or should I say. Introduces a stronger and more appropriate expression than the preceding one.
- His face was dirty, nay filthy.
- 1748, David Hume, chapter 18, in 'Enquiries concerning the human understanding and concerning the principles of moral', London: Oxford University Press, published 1973:
- 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,
nay (plural nays)
- A vote against.
- I vote nay, even though the motion is popular, because I would rather be right than popular.
- A person who voted against.
- The vote is 4 in favor and 20 opposed; the nays have it.
- (archaic) A denial; a refusal. 
- (A vote against): yea
nay (not comparable)