Possible Clues:

• No to MacNair
• Scots 'nuh-uh'
• No, to a 6-Down
• Possible response to 'D'ye ken Scots?'
• 'Fat chance, laddie'
• Negative, north of England
• 'Me, ___ cheerful twinkle lights me': Robert Burns
• 'Captain! The engines canna take ___ more!' (line from Scotty on 'Star Trek')
• Burns refusal
• '___ doubt but they were fain o' ither': Burns